The problem comes from the fact that most schools start today after the Easter Holidays and many teachers and students were abroad when the "ash crisis" started.
The academic year in primary and secondary schools in the UK is divided into three terms: Autumn, Spring and Summer (traditionally called Christmas, Easter and Summer terms, these names have changed due to political correction). In the middle of each term there is a week holiday called half term. There are also some bank holidays scattered along the year as well as the main vacation periods: Summer, Christmas and Easter.
For more detailed information about the British school calendar you need to check the information about a particular area. Here is the calendar for 2009/10 at the London Borough of Hackney:
The Learning Trust - The Future for Education in Hackney
