A senior London banker has been arrested on suspicion of tax fraud.
The 63-year-old man, who has not been named, was held at an address in the capital on Wednesday morning.
HM Revenue and Customs (HMRC) said the suspected fraud was in relation to a personal tax return and was not related to the man's employment.
Alan Lee, deputy director of criminal investigation for HMRC, said: "Tax fraud is a serious crime and HMRC will not hesitate to take action and investigate where we find evidence of someone not playing by the rules.
"Further information cannot be provided at this stage as our investigation is ongoing."
HMRC described the person as a "senior London bank executive" but a spokeswoman refused to give any explanation about what this meant.