score:1
We canβt answer that without knowing your citizenship. Your Belgian residence permit is irrelevant, it does not give you the right to enter the UK if you need a visa by virtue of your nationality. You can use this tool https://www.gov.uk/check-uk-visa to find out.
If you can enter the UK visa-free, you will need travel ID appropriate to your chosen transport and a passport to enter the UK https://www.gov.uk/uk-border-control/before-you-leave-for-the-uk