Since the Employment Act 2002 became law, working parents of disabled children under 18 have the right to request flexible working arrangements. Furthermore, since April 2007, you also have the right to ask for flexible working if you are a carer of an adult who is a relative or lives at the same address as you.
While you have the right to ask for flexible work in these circumstances, it is important to know that employers are not bound to grant these requests. However, they must give business reasons for refusing a request for flexible working.
Carers also have the right to take unpaid time off work for dependents (the people they care for) in an emergency.
For more information, see Working Carers