HMRC has a duty to protect the VAT system from fraudulent attacks. It has a risk-based approach. Verification of VAT repayment claims is an important part of the Missing Trader Intra-Community Fraud (MTIC) strategy.
Unfortunately it is not possible to disclose the numbers of claims that are subject to verifications, so the requested information cannot be disclosed. To do so would undermine the measure introduced by HM Revenue and Customs to counter MTIC fraud and as such prejudice the assessment and collection of tax.