Replace with a National Sales Tax on all non-essential items. Implemented on a local basis as well to encourage competition between different areas. People who spend more on non-essential items would pay more which is a fairer tax. This could vastly reduce national and local government revenue from a decrease in the tax rate. This may also attract foreigners to move to the UK which could increase tax collected. See the Fair Tax currently being debated in the U.S. for further insights.
Extent of repeal
The entire Act