Call it the Debtors' Last Stand. The estates of Lehman Brothers, the collapsed bank, and Nortel Networks, the collapsed telecoms group, are clubbing together to evade a £2.3bn combined bill from the UK's Pensions Regulator.

For those not familiar, the two firms are each the subject of the Pensions Regulator's most recent notable cash demands, in respect of UK pension funds that were in deficit when the companies went under. The watchdog is after around £150m from the Lehman estate to bail out its UK fund, and a whopping £2.1bn from Nortel for its much-larger scheme. It issued the demand against Nortel in July, and against Lehman a few weeks ago.