This is based on the use of latex paint which is the most popular kind of paint an Oxford painter and decorator will use resources.
Latex paint generally takes about 30 minutes to dry but this is dependent on the temperature, colour, type of paint, humidity in the room and the technique in which the paint was applied by the Oxford decorators. On average the re-coating time is 4-5 hours for most latex products (check the tin of paints label for manufacturer directions and make sure your Oxford painter adheres to them).
It takes longer for darker colours to dry because the amount of colourant is more for dark colours and colourant consists of pigment and glycol which take longer to dry.
Make sure your Oxford painter and decorator does not rush the paint job! Re-coating too fast and rolling into a paint which has not fully dried can cause problems that are difficult to amend. If paint is applied over a finish that is not yet dry the water in the product re-wets the base coat of the paint. The base coat will then re-activate and start to roll off the wall, resulting in a textured effect which will not look good. If this does happen it will mean your Oxford decorator will have to sand down the wall and wait till the paint has dried, so by rushing you will in fact make the job take longer.
After about 2 weeks the paint will have reached full hardness and achieve maximum durability. If the paint is a washable type after 2 weeks it can be then washed using soap and water with a sponge.