The boss of BT's corporate IT operation, where a dire performance has forced the telecoms company to axe 15,000 jobs and slash its dividend, pocketed more than £3.5m in his last year, reigniting the furore over rewards for failure.

The award for François Barrault was branded as "outrageous" by union leaders and has forced BT to introduce a clawback scheme designed to prevent any director collecting a huge payout, despite the poor performance of their business, in the future.

Barrault was ousted in October last year as the dreadful performance of his business led to a monumental profit warning by BT. The company attempted to prevent him collecting his cash and shares but after taking legal advice was forced to admit that his contract allowed the payout.

Last year Barrault received £1.25m in salary and benefits such as his company car, home security, dental cover for his family and even his own financial counsellor. It also included a housing allowance, school and social club fees. There was a £1.6m termination payment and he also collected £283,000 worth of shares under the company's long-term incentive plan, £264,000 worth of shares under its deferred bonus plan and had £135,000 worth of unrealised gains on his share options.

Tonight a spokesman for the company admitted: "We are disappointed at having to make the payment to François but BT honours its legal and contractual obligations."

Andy Kerr, deputy general secretary at the Communication Workers Union, was scathing about the award, which comes as BT introduces a company-wide salary freeze and is slashing contractor's pay by as much as a third. "François Barrault's payoff is outrageous. He is being rewarded for failure," he said. "This gives the wrong signal to staff at a time when they are being asked to make significant changes to the way they work."

Once touted as the saviour of the telecoms company, BT Global Services made wildly over-optimistic projections of the potential profitability of a clutch of government and corporate contracts, including its involvement in the multibillion-pound upgrade of the NHS's IT systems.

BT was last month forced to take a £1.6bn writedown in the value of the business and embark on an expensive restructuring.

The unit's poor performance has created a cash squeeze at a time when BT needs to pump £525m a year into its pension fund, the largest private-sector scheme in the UK, to cope with its widening deficit. Shareholders, including hundreds of thousands of pensioners, have seen their dividend payout more than halved.

Barrault's behaviour is in contrast to that of his replacement at BT Global Services, Hanif Lalani. He was due a small bonus as a result of his previous work as finance director but has decided not to take it.

The chief executive, Ian Livingston, is likely to come under intense scrutiny for his decision to accept a £343,000 bonus for last year despite missing all the company's targets. His total award for last year was £1.17m but he has pledged to use his bonus to buy BT shares.

The bonus, awarded as BT had met some of its customer service and environmental targets, is one of four given out for the year ending March 2009, according to the company's annual report and accounts published today. Gavin Patterson, who replaced Livingston as head of BT Retail, picked up a £162,000 bonus, taking his pay to £698,000, while new finance director Tony Chanmugam pocketed a £103,000 bonus, taking his pay to £275,000.

The fourth BT executive to pick up a bonus was Ben Verwaayen, who quit as chief executive last summer and whose role in the creation of BT Global Services has come under scrutiny since the performance of the business has come to light. Verwaayen pocketed more than half a million pounds for his last three months with the firm, including a £300,000 bonus.