I have a Jamaican Passport and a Updated Permenant Resident Card and I will be needing to travel to the United Kingdom for a total of 7 days . What other documents do I need for this trip ?
To visit the UK for tourism purposes, The holder of a Jamaican passport needs a visa.
It is your "nationality as shown on your passport or travel document" which matters. So far as I know, being a resident alien in the US does not confer any non-visa status or visa-waiver status.
I think that, although useful when re-entering the US, the permanent resident card is not regarded as a "travel document" you could use to enter the UK. Even if it were, it would not alter your nationality.