It depends on your contract. Most modern mid-senior UK employment contracts have an explicit garden leave clause that lets the employer put you on garden leave at any point during your notice. If yours has that clause, your employer can invoke it unilaterally and you don't have to agree. If your contract is silent on garden leave, the employer can request it but can't insist.
Garden leave is one of three ways a UK notice period can resolve: you work it normally, you take payment in lieu of notice (PILON) and leave immediately, or the employer keeps you employed but tells you to stay home. The third one is garden leave. It pays your full salary, keeps your benefits running, and keeps every contractual obligation in force. Crucially, employment doesn't end until the original notice period was due to end.
Whether the employer can force you onto garden leave comes down to the wording of your contract. The clause is usually called 'Garden Leave' explicitly. It typically says something like 'During any period of notice (given by either party) the company may require the employee to remain away from the place of work, refrain from contacting clients or staff, and abstain from performing any duties.' If your contract has that wording, the employer can use it without your consent.
If your contract doesn't have a garden leave clause, the position is more nuanced. You still have an implied right to work, particularly in roles where being out of the market damages your career (specialist tech, sales, anything where current market presence matters). Employers can request you stay home, but if you push back, courts have sometimes sided with the employee. In practice, most employees prefer paid leave at home to a tense office presence and don't fight it.
Employers use garden leave most commonly when you're leaving for a competitor. The single biggest benefit, from their side, is freezing your knowledge at the moment of resignation. The longer you stay in the office, the more current information you'll carry over: live deals, internal strategy, fresh client relationships. Garden leave caps that at the day you resigned, even though your employment formally continues for weeks or months after.
Other common reasons include protecting client relationships during the transition (sales-heavy roles where the successor needs uncontested time with clients), keeping sensitive transitions clean (executive exits), or just because the employer has decided you won't add much in the remaining time and prefers a clear break. None of these need to be explained to you; the contract gives them the right.
The financial side is the same as working notice. Full salary, normal benefits, pension contributions continue, share scheme participation usually continues. The key practical thing to know is that holiday accrues during garden leave (and many employers require you to use accrued holiday during the period rather than be paid out). Bonus eligibility depends on the scheme rules; most require you to be employed AND not on notice on the payment date, so garden leave usually fails that test.
The thing to model carefully if you have a non-compete clause is the date arithmetic. Restrictive covenants typically run from the end of employment, not the start of garden leave. So a three-month garden leave followed by a six-month non-compete keeps you out of the market for nine months total. The garden leave calculator on this site does that maths. If you're moving to a competitor, this is the most important number to know.
General information about UK employment law. For your specific situation, contact ACAS or an employment-law solicitor.