National Insurance Contributions Office
Inland Revenue
Longbenton
Newcastle upon Tyne
NE98 1ZZ
Tel 0191 213 5000

Working Families Tax Credit
Tax Credit Office
Inland Revenue
PO Box 145
Preston
Lancashire PR1 0ZS
Tel 0845 609 5000
Textphone 0845 608 8844

Northern Ireland Tax Credit Office
Inland Revenue
Dorchester House
Great Victoria Street
Belfast BT2 7WF
Tel 0845 609 7000
Textphone 0845 607 6078

Inland Revenue Website
http://www.inlandrevenue.gov.uk