"Given the bank's ever more fragile situation, it became clear that a solution needed to be found so that the bank [could ] reopen on Monday, 21 December 2015, and that a disorderly liquidation with consequences for the financial stability of the Portuguese banking system could be avoided," the commission said in a missive to Portuguese deputies.

The statement came in a 59-page letter addressed to the parliamentary committee of inquiry into Banif, which Lusa has seen.

In it, the commission argues that it is not charged with banking supervision, the drafting of state aid plans, or the definition of strategies for the resolution of banks.

"The role of the Commission is to guarantee that all the measures proposed by the authorities are in keeping with European Union legislation, including the rules relating to state aide," it writes.

Over the weekend when the sale of part of Banif to Banco Santander Totta - as part of its resolution - was decided there was "close coordination" at the political level between the European commissioner for competition, Margrethe Verstager, and Portugal's finance minister, Mário Centeno, the letter states.

Late at night on Sunday 20 December, the Ban of Portugal and the government announced the resolution of Banif, the sale of some assets to Santander Totta and the transfer of others - many of them deemed toxic - to a holding company, Oitante.

The operation surprised many observers by the scale of state aid involved - which was initially €2.255 billion, requiring an amending state budget. On top of this there were guarantees worth some €746 million and the loss of some €800 million that the state had lent Banif in 2012 and which had not been paid back.

In all, excepting the €150 million paid by Santander Totta, the cost of taxpayers could be as much as €3.6 billion.

The parliamentary committee of inquiry into the process on Tuesday heard the minister of finance for a third time.