Even if Camelot's present ticket sales are maintained, the total going to charities has been estimated at £9.6bn, £2.6bn less than the £12.2bn it predicted during the bidding process.
The estimate – from analysis by the Financial Times – is £900m less than the £10.5bn raised in Camelot's first seven-year licence period, and does not take into account the £2.2bn to be diverted from good causes to pay for the Olympics.
A Camelot spokesman said the £9.6bn estimate before Olympic deductions made "unjustified assumptions" about future sales but would not offer an alternative prediction.
Camelot's bid for a third seven-year licence, to extend its contract to 2016, is expected to be confirmed in August, since its only rival is the little known Indian lottery firm of Sugal & Damani.
Meanwhile, the most recent Camelot annual report has revealed that the total salary package of chief executive Dianne Thompson went up 44.8 per cent, from £654,000 in 2005 to £947,000 in 2006. Over the same period, lottery ticket sales went up 5.17 per cent or £246.7m to just over £5bn and funding for good causes rose 3.74 per cent or £50.5m to just under £1.4bn.