http://news.bbc.co.uk/1/hi/business/7119288.stm
The European Commission is to investigate whether BT is getting unfair financial help from the state with its pension liabilities.
The telecoms operator benefits from a government guarantee that exempts it from making some pension contributions.
The guarantee - which sought to secure BT workers' pensions after it was privatised - may give it an advantage over its competitors, some claim.
But BT said it did not believe the exemption "raises state aid issues".
Fair play?
The commission said it did not challenge the principle of a state guarantee.
But following a complaint it received last year, it wants to see whether the agreement gives BT a financial advantage.
The guarantee exempts the telecoms firm "from certain common law financial obligations", such as paying a levy to the Pension Protection Fund, the commission said.
This fund was created by the UK government in 2004 to "guarantee pensions when sponsor companies go bankrupt", it added.
Only companies with a state guarantee can opt out of the fund.
But BT said that the guarantee only benefits those who were part of the BT pension scheme when it was privatised.
"BT and the trustees consider that there is an effective and equitable system for pension protection in the UK which does not raise state aid issues and will cooperate fully with the commission in its investigation," the firm added.