The Pensions Regulator has begun enforcement action against a number of parties including Sir Philip Green after failing to reach a deal to plug BHS’s £571m pension deficit.

In a dramatic development, the regulator, which has been in talks with Sir Philip and his Taveta group of companies over the retailer’s pension fund since BHS collapsed in late April, issued a warning notice to the Top Shop entrepreneur setting out why it believes he is liable to support the scheme.

Although the talks have been ongoing for more than six months, the amount he has being offering to date has not been made public.

The notice follows an investigation by the regulator into the collapse of BHS and its troubled pension fund, including poring over some 100,000 documents.

Similar enforcement notices - each of which is believed to run to more than 300 pages - have also been issued to Taveta, to Dominic Chappell, the man who infamously bought BHS from Sir Philip 13 months before it collapsed, and to Retail Acquisitions, Mr Chappell’s company.