Labour intends to force people earning £1m and above to publish their tax returns, documents show. If this becomes law it will affect 21,000 Britons, according to calculations by the Institute for Fiscal Studies (IFS). It would also mark a shift in the UK’s tax policy, sweeping away the notion that everyone’s tax affairs are private.

The initiative, first mooted in 2007 by John McDonnell, now shadow chancellor, is detailed in a document called Labour’s Fair Tax Programme. It is thought to have been posted on Labour’s website on Friday, November 22, when the party launched its manifesto.

The document states: “The public has lost faith that our tax system is a level playing field, with multinationals dodging tax and the wealthy getting away with