1. Turn off the water at the main.or--
2. Look under the sink for an isolating valve for the hot water.
If it is a modern installation, the valve will be an "in line" one that can be turned off with a screwdriver.
If you cannot find a valve, you will have to drain all the hot water off before you can procede.
3. Remove the red inset on top of the tap with a small screwdriver or nailfile. Under this, will be a Phillips screw. Undue this screw and take off the top of the tap.
4. With an adjustable spanner, remove the innards of the tap.( this will be brass and not chrome.) IT MAY BE VERY TIGHT>
5. Inspect the washer, and replace if it looks worn or cracked.
( Your local B&Q will be able to help.)
6. Lubricate all the moving parts with Vasiline and re-assemble.
DO NOT USE OIL OR GREASE AS THIS MAY TAINT THE WATER>
Hope this helps Keith
keith howard, March 2006