Up to 3,500 people have objected to the plans from South West Trains which will hit several stations locally. And a further 3,000 commuters have signed a petition calling on the train company to make a U-turn.

Now the Rail, Maritime & Transport and Transport Salaried Staffs' Association unions have backed the protests by the Passenger Focus Trust.

RMT general secretary Bob Crow said: 'This is a good day for passengers and rail workers alike, and Passenger Focus is to be congratulated for putting the case against cuts that are as unjustifiable as they are unpopular.

'At a time when passenger numbers are growing and footfall through stations is at record levels, we need to see more staff on stations, not fewer, and we have written to the Department of Transport urging it to uphold the objection lodged by Passenger Focus.'

Under the plans Cosham Station ticket office will open at 8am instead of 6.10am on Saturdays, and shut at 2.30pm instead of 7.45pm.

Bedhampton Station's ticket office is set to close at 9.45am during the week and will be shut throughout the weekend.

Portchester Station will shut three hours earlier on weekdays and stay shut during weekends.

Portsmouth Harbour Station will open at 9am on Sundays, instead of 6.40am, and close at 4.30pm, not 8.10pm.

Passenger Focus has the power to challenge the planned cuts, and has urged the government to tell SWT to shelve them.

The organisation says it has received more than 3,100 postcards and 360 letters and e-mails objecting to cuts in ticket office opening times. The RMT and TSSA unions also submitted a petition of more than 3,200 signatures.

SWT said a decision may not be made for several months.

Spokeswoman Simone Spinks said: 'We will read the comments with interest. Then we'll have discussions with representatives from Passenger Focus. We don't know how long a period that will take.

'Should everything go ahead with the proposal, there won't be one day for all station changes.

'It will be phased over time.'