An employee brings in a call-out notice. They expect to leave within weeks, hold a key customer relationship and are the only person who runs one of your systems. The immediate problem looks like staffing, but the employer also needs to protect legal deadlines, make the right payroll changes and preserve the employee’s route back. A useful mobilisation plan deals with all of those issues together, with one named person coordinating the response.
Separate routine training from formal mobilisation
GOV.UK says employers do not have to grant time off for reservist training, although they can choose to provide it. Check your contract, reservist policy and any specific commitments before deciding a training request. State whether additional leave is paid or unpaid, how requests are made and how managers will consider the training calendar alongside operational needs.
Mobilisation is different: the reservist receives a call-out notice for full-time service. Do not run that notice through an ordinary holiday-approval process or tell the employee that a busy period cancels their obligation to report. GOV.UK says notice is usually 28 days, but urgent circumstances can mean less.
The Ministry of Defence’s employer toolkit explains that the Reserve Forces (Safeguard of Employment) Act 1985 protects employment and provides reinstatement rights, subject to conditions. Dismissing someone without their consent solely or mainly because they are liable to mobilisation can be a criminal offence. Treat any proposed dismissal or restructuring affecting a mobilised employee as a matter needing specific advice.
GOV.UK: reservist rights and training ↗ · MOD: reservist employer toolkit ↗
Record the notice and act promptly if serious harm is likely
Keep the call-out documentation securely and record when it was received, the reporting date, expected duration and the service contact. Arrange a meeting with the employee and bring payroll and the operational manager into the planning process. Avoid circulating deployment details beyond the people who need them.
An employer can apply to delay or cancel mobilisation where it would seriously harm the business. GOV.UK gives examples involving financial harm or an inability to provide goods or services. Its guidance requires an application within seven days of receiving the call-out notice; a late application needs the adjudication officer’s permission. Contact the person named in the notice or the relevant adjudication officer promptly and follow the written application process.
Prepare concrete evidence: the work affected, available cover, costs, critical deadlines and alternatives considered. A preference to keep a valued employee at work is not the same as demonstrating serious harm. Continue contingency planning while the application is considered; do not promise the employee that the business can simply veto the call-out.
Design temporary cover around a protected return
List the employee’s live work, delegated authority, customer commitments, system access and specialist tasks. Decide which work must continue, which can move and which should pause. Give the replacement enough supervised handover time rather than assuming that a password and an inbox provide a complete transfer.
If you recruit temporary cover, describe its purpose and likely duration accurately. Review the employment terms and ending arrangements before making an offer. A permanent promise to a replacement can create an avoidable problem when the reservist is ready to return; equally, calling a contract temporary does not remove the replacement’s employment rights.
Agree a proportionate contact plan with the reservist: who will provide important workplace updates, which channel is suitable and what to do if dates change. Do not expect them to keep running the civilian job during service. Record business changes that may require refresher training on return, and give the cover arrangement a review date.
Give payroll a mobilisation instruction, not a resignation form
GOV.UK explains that MOD meets salary and pension-contribution costs during mobilisation. Check the employee’s arrangements, any enhanced employer commitments and the pension process before changing payments. If you voluntarily continue salary or pension contributions, those payments cannot be reclaimed through the employer financial-assistance scheme.
Payroll reporting depends on the expected service period. For service of less than 12 months, GOV.UK directs employers to use the irregular-payment indicator in the next Full Payment Submission once service starts and the specified BR M1 or BR W1 tax code. For service expected to exceed 12 months, it gives a different process involving a leaving date, P45 and a new payroll ID on return.
The guidance expressly says not to issue a P45 or enter a leaving date merely because service originally expected to last less than 12 months subsequently runs longer. Payroll reporting does not settle the employee’s reinstatement rights. Have payroll verify the applicable route, including any borderline duration, and keep the employment record clear about why the absence occurred.
Put the employer plan in writing.
HR + SAFETY can help your business align the absence record, temporary-cover terms and manager communications.
Discuss a reservist mobilisation planClaim eligible support while the evidence is available
Financial assistance may cover eligible additional replacement costs, recruitment expenses, handover, overtime and training. It is not a reimbursement of every business loss: lost profit, turnover and goodwill are excluded. Check the current claim form, limits and supporting evidence before treating any amount as recoverable.
GOV.UK also describes an employer incentive payment of £500 a month for an eligible full-time mobilised employee, with pro-rata payments for part-time employees and part-months. Its conditions include private or charity sector status, annual turnover no greater than £25.9 million in the preceding 12 months and no more than 250 employees or partners at mobilisation.
Diarise the claim windows. The normal final deadline is four weeks after service ends; training costs should be claimed within eight weeks of the training ending. Keep invoices, additional-cost calculations and approvals together, and claim as costs arise rather than reconstructing everything after demobilisation.
Prepare for reinstatement before the employee asks to return
GOV.UK says reservists should write as soon as they know when they can return, and no later than the third Monday after their last day of service. They receive leave after service, and employers cannot require them to return before that leave ends. An earlier return requires permission from the commanding officer or demobilisation centre.
The starting point is the former type of job on the same terms and conditions. Where the original occupation and terms are not reasonable and practicable, the statutory framework requires consideration of the most favourable reasonable and practicable alternative. Do not assume that filling the role during the absence removes the obligation.
There is also a required period of re-employment linked to pre-mobilisation service, with minimum periods of 13, 26 or 52 weeks. Check the applicable band and the statutory conditions. If a deadline was missed, health affects availability or the business has changed substantially, obtain advice before refusing reinstatement.
Agree a return meeting, system access, an update on changed procedures and any refresher training. Ask what work-related support is needed without assuming that every reservist returns with a health problem. Set an early review date so the employee and manager can resolve practical difficulties.
GOV.UK: returning to work after mobilisation ↗ · Reserve Forces (Safeguard of Employment) Act 1985 ↗
The employer’s mobilisation checklist
Official guidance was checked on 8 November 2026. This is a practical UK employer overview; individual call-out, reinstatement and payroll decisions depend on the notice, employment history and applicable statutory conditions.
- Identify whether the request concerns routine training or a formal call-out.
- Record receipt and reporting dates, and review any serious-harm application immediately.
- Assign one coordinator and agree a realistic handover and temporary-cover plan.
- Confirm payroll, pension and contractual-benefit arrangements in writing.
- Preserve claim evidence and diarise financial-assistance deadlines.
- Keep important workplace updates and return planning active during the absence.
- Check reinstatement conditions, the role offered and the required employment period.
- Arrange a supported return with training and a review date.
Treat mobilisation as a planned absence with specific employment protections. Control the notice, cover, payroll and claim deadlines, then make the return arrangements as deliberate as the departure.
This guide provides general information for UK employers. It is not legal advice and should not replace advice based on the facts of a specific matter.