The paintings were stolen in 1994 and recovered several years later

Last month the gallery denied BBC claims that it paid a ransom for Shade And Darkness or Light And Colour.

It has now released papers that show �3.1m was paid to a lawyer in 1999.

It said the possibility that this was passed on to the thieves "was an unavoidable and inevitable consequence of recovery operations of this nature".

Thieves arrested

The 19th Century works - Shade And Darkness: The Evening Of The Deluge, and Light And Colour (Goethe's Theory): The Morning after the Deluge - were stolen from the Schirn Kunsthalle in Frankfurt in 1994.

On loan from the Tate to the exhibition Goethe And The Visual Arts, the paintings had been insured for �12m each.

Three thieves and a driver were arrested in 1995 and convicted in Germany in 1999.

In November the BBC documentary Undercover Art Deal claimed payments of around �3m were made to secure the return of the artworks.

A Tate spokeswoman responded by saying the money was paid for information and that "no ransom was paid".

'No control'

However, the Tate has now released documents that show it made a payment to German lawyer Edgar Liebrucks, who "claimed to be in direct contact with those who had possession of the paintings".

"However, once Tate had paid the money to Edgar Liebrucks, it had no control over that money," the gallery said in a statement.

"Tate does not know to whom Mr Liebrucks made payment of the monies he had received from Tate."

The gallery "consulted extensively" with British and German authorities for all payments it made to Mr Liebrucks.