I don't know for definite, but I think the answer is no. What you can do is open a $ currency account based in the UK - several banks offer this, although there are generally associated charges or other requirements.
We have recently opened a Citibank $ account
www.citibank.co.uk. As long as you pay in your salary, or maintain an equivalent $ balance of £2000, there are no charges
If you are HSBC Premier account holder, you can open one without much difficulty, but as a normal HSBC customer, there are charges for having the account, and for writing cheques etc.
Hope that helps a little.