EXISTING tram lines across Greater Manchester could be scrapped if the Metrolink's Big Bang expansion is scuppered.

Routes from Bury, Eccles and Altrincham into Manchester are under threat because the lines are ageing and in need of repair.

Part of the £500 million expected from the Government to fund the tram network's expansion -- the so called Big Bang -- included £100 million to replace the existing three lines. Cash is also needed to buy more trams to ease the problem of too few carriages and too many passengers.

But the repair work is now in jeopardy, leaving the whole Metrolink system in the balance since the government has decided not to fund new lines to Rochdale, Oldham, and Manchester Airport.

It could spell travel torment for commuters who journey into Manchester from Bury, Radcliffe and Whitefield. A lack of future investment could lead to contracts on existing lines being cancelled or even closed.

Transport Secretary Alistair Darling has turned down funding for the new lines because of concerns about the cost and profitability of light rail.

But money is depserately needed to improve tracks, modernise an ageing fleet and boost the limited number of spare trains.

Roger Jones, chairman of Greater Manchester Passenger Transport Authority, said: "Renewal and regeneration was an integral part of our package when the government said Yes to Metrolink 12 years ago.

"Today, it is no surprise that the existing services need looking at. If we go ahead with our expansion, we are still in the time frame for this programme of renewal and regeneration.

"We have launched a major lobbying campaign aimed at changing the government's mind.

"The message coming from the MP's and councillors is that this campaign will be successful."