The money, nearly £400,000 of which is in legal expenditure, is in addition to internal costs for the Pensions Regulator (TPR), which has 16 staff working on the probe, though not all of them full-time.
The figures, disclosed to City A.M. in a freedom of information request, show TPR racked up costs of £46,533 in 2015/16, after its investigation was launched in March 2015, and then £1,318.308 in 2016/17 until 31 October.
TPR intensified its investigation into Green, who sold BHS to Retail Acquisitions last year, in November, with the body seeking redress for 20,000 pension scheme members.
Labour MP Frank Field, chair of the work and pensions committee and a vocal critic of Green, told City A.M.: “I hope they add these costs to his bill.”
TPR said in a statement:
When considering cases of avoidance, we will not hesitate to invoke our regulatory powers to protect members and PPF levy payers if appropriate. We may consider more than simply the financial amount we can achieve on behalf of members, for example by launching a case we know we can send a clear message that we will not tolerate avoidance activity.
On the occasions when we have had to use our anti-avoidance powers, this has led to the recovery of over £650m for pension schemes, including through settlements without the need for formal proceedings. This is very significantly in excess of what it cost us to pursue these cases.
Today, a cross-party group of MPs called on the government to give TPR greater powers to prevent another “BHS pension fund-style disaster”.
A report by the work and pensions select committee proposed trebling the amount of fines TPR can levy. In the case of BHS this would equate to regulators being able to slap a charge of up to £1bn on key protagonists.
The report called the current system of regulation "clunky and concentrated" and, in relation to the BHS saga, criticised the regulator for taking two years to intervene.
As part of the wide-range of proposals to give TPR more teeth, the report proposed new rules for situations where TPR should give clearance prior to major M&A transactions.
Echoing calls by the former chair of the Pension Protection Fund, Lady Barbara Judge, MPs said certain corporate transactions should be subject to mandatory rather than voluntary sign-off by TPR.
The intention of such changes would be to ensure M&A activity would not lead to pension scheme members being adversely affected.