Weekend train journeys could take longer next year on one of the busiest routes in the region.

The King's Lynn to King's Cross line, served by Great Northern trains, may increase up to 12 to 14 minutes on Saturdays under new timetable proposals.

Figures released on December 1, on estimated station usage, showed King's Lynn, Downham Market, Ely and Waterbeach stations are four of the region's fastest growing stations.

But despite the sustained growth in passenger numbers, authorities and rail officials believe the current timetable proposals for longer journeys risk jeopardising the Fen Line's success story.

Earlier this year, West Norfolk council, Fen Line Users Association (FLUA) and the King's Lynn Business Improvement District Ltd called on the government to improve existing journey times on the route and to honour their commitment for half-hourly trains.

The three bodies believe the current proposals give added urgency to these calls.

Councillor Brian Long, leader of West Norfolk council, said: 'We've heard much about the promised work on Ely North Junction that is to take place, but that will inevitably be a long process.

'We also want the single-line sections between there and King's Lynn returned to a two-track line. The single-track bottlenecks result in a sub-standard level of service, which Great Northern is now proposing to downgrade further, with even longer journey times.

'Our line is one of East Anglia's most consistent heavy-hitters – official figures just out show what we know already from our packed trains – passenger numbers are up yet another year.

'We urge rail users to respond to Great Northern's consultation and tell them what they think.'

Colin Sampson, chairman of FLUA, said: 'We've said before that more and more people are travelling to Cambridge and London and that they expect a decent train service.

'The growth isn't a flash in the pan – just look at the official statistics, which show strong passenger growth year after year.

'Not delivering the promised 'half-hourly' frequency is bad enough, but now they're thinking of slowing things down on top of that. FLUA thinks fares should be reduced to compensate, not going up again.

'Many journeys would be 15pc longer if this goes through, so we're looking for at least a 10pc price cut on all fares.'

Darren Taylor, chairman of King's Lynn BID Ltd, added: 'King's Lynn businesses are getting increasingly fed-up with false promises and a lack of action from Great Northern.

'I welcome the bigger trains, but not the long delays before they are to be introduced, maybe over a year away, but we need them twice an hour, all day.

'I'm concerned that the Fen Line, and King's Lynn specifically, is yet again being overlooked in favour of investment that will benefit other towns and cities in the East. We need to make our dissatisfaction clear to Government.'

The proposals by Govia Thameslink Railway, which runs the service, are out for consultation until Wednesday, December 20.