A lack of costings, growing levels of fraud and excessive complexity mean that the Treasury needs to be more transparent about multi-billion pound tax breaks, MPs have said.

The Treasury committee has called on HMRC and the Treasury to provide a breakdown of how the business tax relief scheme, which currently offers over 1,800 separate tax schemes, is operated

Following several evidence sessions, MPs said it was inexcusable for HMRC not to provide detailed costings about the effectiveness of hundreds of tax breaks, demanding it publish cost data for all tax reliefs for the 2025/26 tax year onwards.

They also stressed that the Government should review existing tax reliefs to identify opportunities for simplification and to monitor for abuse and fraud.

According to the Treasury committee, only 105 of the 1,180 reliefs are fully costed, with an annual bill of £195bn, while 815 reliefs are completely uncosted.

Harriett Baldwin MP, chair of the Treasury Committee, said: "Our tax system is too complicated, and the proliferation of un-costed tax breaks adds to that complexity.

"While some reliefs are very effective, others are prone to abuse or simply lie dormant, cluttering the ever-expanding tax code.

"HMRC and the Treasury need to work hand in glove to get a grip on the complexity, lack of transparency and potential for abuse."

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