By accepting a new role in the UK, I shall be treated as a "bad leaver" by my current employer and forfeit significant equity and deferred payments: is there anything that I can do?
It is common in the UK for new employers to "buy out" amounts that an employee would forfeit by leaving their current employer, although there are limits to what some employers can offer (especially those in regulated sectors).
Ultimately, this will be down to the strength of your bargaining position. Where a "buy-out" arrangement is entered into, the payment will typically be paid on or around the commencement of your employment (sometimes in stages) with claw-back provisions attached: these will normally require you to repay all or part of the payment if you leave your new employment or your employment is terminated for cause within a certain period.
Before entering into detailed discussions with a prospective employer on such points, it is worth considering the confidentiality obligations owed to your current employer to ensure that nothing you share with the prospective employer could amount to a breach of those.
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.