HM Revenue and Customs - www.hmrc.gov.uk
PAYE Rates and Allowances: www.hmrc.gov.uk/rates/it.htm
NI Rates and Allowances: www.hmrc.gov.uk/rates/nic.htm
Statutoty Sick Pay:www.hmrc.gov.uk/employers/ssp-faq.htm#a
DWP - The Department for work and pensions.
(Parts of the former Departments of Social Security, Education and Employment
Service.) They provide a single point of delivery for jobs, benefits
advice and support, through Jobcentre Plus.
Child Support Agency - For information about collection and payment of Child Support Maintenance.
Childcare Vouchers - For information about Child Care Vouchers.
Tax Credits - You may be entitled to working families tax credits. To find out if you are, use the calculator here