The stinging report by two committees of MPs on the failure of BHS left two points hanging in the air. First, the MPs did not say how much Sir Philip Green, whose reputation was demolished over 59 pages, should pay to cover the shortfall in the BHS pension schemes. It merely said Green “has a moral duty to act, a duty which he acknowledges”.

Second, the committees did not recommend that Green should be stripped of his knighthood. Even Frank Field, chair of the work and pensions committee, who had previously raised the prospect of a de-gonging, confined himself to a heavy hint outside the pages of the report. “What kind of man is it who can count his fortune in billions but does not know what decent behaviour is?” asked Field.

Such relative restraint on the part of the MPs was sensible. It is up to the Pensions Regulator to determine the true size of the shortfall. And it will be the Honours Forfeiture Committee that decides whether SPG, as the tycoon’s hangers-on refer to him, should be plain PG again.

But the report provides ammunition by the bucketload for both bodies. In 2000, Green bought a business with a surplus in its pension scheme of £43m and then paid his family dividends far in excess of BHS’s profits. In 2015, having failed to fund the schemes adequately or complete a restructuring to the satisfaction of the regulator, he sold BHS with a £345m pensions shortfall.

The buyer was the “wholly unsuitable” Dominic Chappell, a twice-bankrupt individual who was out of his depth. The verdict on Green is damning and unequivocal. He “overlooked or made good each of Chappell’s shortcomings and proceeded with a rushed sale regardless”, says the report.

Then he attempted to blame everybody apart from himself. Some of those other actors, especially professional advisers such as Grant Thornton and Olswang, indeed failed in their duties while collecting fees that have still not been disclosed. But the fateful sale of BHS to an incompetent chancer with inadequate funding was driven “personally” by Green, says the report.

Armed with that conclusion, the Pensions Regulator should press for Green to repair the pension damage in full. It would be a disgrace if even part of the shortfall is covered by the Pension Protection Fund, the lifeboat scheme that is supported by a levy on 6,000 other defined benefit pension schemes. Green – or, strictly speaking, Lady Green, as the ultimate owner of the family empire – is rich enough to pay. Let the couple do so rather than shuffle off part of the shortfall on to other companies’ schemes.

Estimates of the size of the bill vary. On one accounting measure, the combined shortfall in BHS’s two schemes was £571m at the point of collapse. A few technical tweaks, such as cash buyouts for members who are decades away from retirement, may be permitted to reduce the cost. But is hard to see how, if the Pensions Regulator is doing its job properly, Green could be asked for less than £400m.

If that feels daunting, even for a billionaire, Green has only himself to blame. The report describes how BHS “declined to make the employer contributions necessary to maintain the sustainability of the pension schemes over the duration of Sir Philip Green’s period in charge”.

In the early years, trustees’ demands for higher contributions were resisted on the grounds that investing in the business would be more lucrative; then, when BHS faltered, beefier payments were deemed unaffordable. Green let a small pensions shortfall become towering. Whether the correct number is £400m, £500m or more, the buck still stops with him.

The knighthood question is only slightly trickier. Gongs, in theory, are not meant to depend on the future good behaviour of the recipient, assuming no laws have been broken. In practice, however, the BHS shambles, as with Fred Goodwin at Royal Bank of Scotland, surely falls into the exceptional category. Goodwin’s award for services to banking was impossible to maintain after the bank collapsed. Similarly, Green’s knighthood for services to retailing looks absurd in light of events.

The pragmatic compromise in the interests of BHS pensioners is probably this. If Green pays up in full and without further fuss, he can keep his gong. The rest of us will just laugh (again) at the silliness of presenting honours to business people before their careers and character can be judged.