If you already have a degree (in any subject), there's the option of a two-year work-based training programme supported by off-the-job learning. You'll earn a graduate diploma in Professional Policing Practice once you've completed your probation.
Alternatively, Police Now offers two-year national leadership development programmes, specifically designed for graduates.
Some forces are also still offering the Traditional (IPLDP) entry route, which can be accessed by graduates and non-graduates. It’s being phased out but if your chosen force is still offering it for now, it might still be the best route for you.