Sir Philip Green told rescuing BHS pension fund will cost more than £300m

The BHS pension scheme is deep in deficit and no longer has the company to support it.

As things stand, it is set to be bailed out by the Pension Protection Fund, leaving 20,000 members facing the prospect of receiving less generous incomes in retirement.

On Tuesday Sir Philip Green restated his determination to rescue the BHS pension scheme.

Dominic Chappell says Sir Philip made a similar pledge when he sold BHS to him in March last year.

"If Sir Philip had delivered on his promise [to deal with the pension deficit] there would be 11,000 [people] still in employment, British Home Stores would still have its doors open and Sir Philip would have saved himself a vast amount of money," Chappell told ITV News.

Chappell claims that the anti-avoidance investigation - launched by the Pension Regulator immediately after he bought the company - was a "major factor" in BHS's eventual failure, frustrating attempts to borrow money.

Chappell, whose role in the demise of BHS was also heavily criticised by MPs, insisted Sir Philip should be stripped of his knighthood, even if he does now deal with the pension shortfall.

But he also expressed sympathy for the way Sir Philip was treated by MPs in yesterday's debate in the House of Commons.

"I think MPs were baying for blood, I thought it was a pathetic show", Chappell said.

"To a certain degree it is a witch-hunt but Philip has over-stepped the mark."

Tonight, in a statement, Sir Philip described Dominic Chappell's allegation that he'd broken a promise to fix the BHS pension deficit as "extraordinary and unfounded".

He said his company, Arcadia Group, had committed up to £50 million to resolve the issue and he added that Chappell and Retail Acquisitions Ltd "entered into various covenants relating to the pension as part of the purchase agreement".

Sir Philip did tell MPs he would "sort" the problems with the BHS pension four months ago when he appeared before the select committee investigating the company's collapse.

Since then discussions with the Pensions Regulator, the Pension Protection Fund and the BHS pension trustees have been ongoing.

As I have explained previously, Sir Philip and his advisors, Linklaters and Deloitte, are working up a plan that will allow 13,000 members to walk away from the pension scheme with a cash lump-sum.

The 7,000 members who remain in the scheme will have their full pension guaranteed, although they will have to accept less generous annual increases.

The basic structure of the deal appears to be acceptable to all sides, the sticking point seems to be money.

Sir Philip is keen to agree a deal that exonerates him from any future liabilities.

The pension authorities are conscious the BHS pension scheme would therefore be without a sponsor and are determined to ensure it is sufficiently well-funded to survive without falling back into the arms of the Pension Protection Fund at some later date.

On Tuesday The Pensions Regulator stated publicly that it was yet to receive a "credible" proposal from Sir Philip.

I'm told that, in private, it has been made clear to Sir Philip's advisors that more than £300 million will be required to ensure the long-term viability of the scheme - a sum that would represent a significant chunk of the billionaire's fortune.

None of the parities involved in the talks are willing to comment on the matter.

These negotiations are complicated, nothing like this has been agreed before. There is no guarantee that common ground will be found.

Sir Philip says he is trying to secure the pensions savings of BHS's former staff as an act of goodwill.

The Pensions Regulator is currently investigating whether he has a legal obligation to do so.