Travellers are facing a rise in Tube fares of more than 5% as a second 24-hour strike threatens to cripple the network.

Mayor Ken Livingstone has approved the increases which will take the minimum cost of a journey in central London to �2.

The new fares come into effect in January and follow this year's rise of up to 11%.

Members of the Rail Maritime and Transport (RMT) union and the drivers' union Aslef will go on strike from 2000 BST.

Fare rises

Peak Travelcard Zone 1-4 - �7 Single to Zone 1 - �2 Single from Zone 6 - �3.70

The new fares will boost London Underground's funds by �20m.

Meanwhile with no end in sight to the pay dispute, services during Tuesday evening are expected to reduce rapidly with the last trains leaving central London by 2130 BST.

The network will come to a standstill on Wednesday and will not be back to normal until Thursday as trains are returned to their correct starting places for the timetable.

It is the second 24-hour stoppage by the two unions as part of a dispute over pay.

London Underground (LU) imposed a 3% pay rise after the unions rejected it.

Mediation plea

The unions claim LU has refused to go to arbitration.

Mick Rix, the Aslef general secretary, told BBC London: "If the government made the phone call to the London Underground management and instructed them to go to independent mediation, then this dispute does not need to take place.

"If that phone call gets to me today I can reconvene my executive committee and ask them to suspend the dispute."

In the first strike last week, millions of commuters had to make their way to work on packed buses and gridlocked roads.