You might consider the Jenkins, in Bloomsbury near the one Lucy mentioned. All rooms have small fridges. http://www.jenkinshotel.demon.co.uk/

In my experience, most hotels and B&B's have a coffee maker or kettle in rooms. We stayed there a few years ago and enjoyed it.

Since you are "last minute", you could try LateRooms.com . Note that the orange prices are discounted, the blue aren't.You can use LateRooms to identify deals and then check out the hotel's own website. You might find the same deal.

For example,the Radisson Edwardian Marlborough has doubles for 75 pounds! http://www.radisson.com/ VAT not included. Breakfast included.

Frances Toronto, Canada