What political party introduced vat in UK?

The original form of VAT, known as the Purchase Tax, was introduced by the grand coalition government between the Conservative Party, the Labour Party, the Liberal Party and the Liberal National Party in 1940. All major reforms to the sales tax since then have been Conservative programmes.

Modern-day VAT was introduced by the Conservative Party in 1973 as a condition of the UK joining the then-European Economic Community. It was set at a rate of 10% on most goods. It became a flat tax (i.e., with only one rate) in 1979 under the Conservatives, when it was raised from 8% to 15% where it stayed until 1991, when the Conservatives increased the standard rate it to 17.5% and also introduced new lower rates for things like energy.

Labour briefly returned to the 1979 - 91 rate of 15% during its last year in power as a short-term measure, but in 2011 the Conservative Party introduced the modern 20% rate.