Hundreds more trains are turning up shorter than scheduled on the first line to be re-nationalised by Labour, figures reveal.

Official data shows 6,191 South Western Railway (SWR) services turned up with fewer carriages than they were supposed to during the first year under state control. By contrast, in the year before re-nationalisation, just 5,017 trains did.

It means the number of SWR trains turning up shorter than scheduled surged by nearly a quarter (23 per cent), leaving potentially thousands of passengers to fight over fewer seats at busy times.

It echoes the scenes of the seventies and eighties, when chronic overcrowding became a hallmark of publicly-owned British Rail before privatisation of the network in the 1990s.

The figures come after the Mail revealed how the proportion of SWR trains arriving a minute or more late soared to nearly half (46 per cent) - from 34 per cent - after being brought back into public ownership.

The Tories’ shadow transport secretary, Richard Holden, said: ‘This is the reality of Labour’s ideological obsessions: a worse service for passengers with more being rammed onto smaller trains.

‘Labour’s answer to every problem is increased state-control. It doesn’t drive up performance - it drives up costs for taxpayers and leaves passengers paying more for less.

‘Under Kemi Badenoch’s leadership, Conservatives will always put passengers and taxpayers first, rather than Labour’s trade union backers.’

Sir Grant Shapps, a former Tory transport secretary, added: ‘Labour's obsession with re-nationalisation has always been driven by dogma, not what works for passengers.

‘If passengers are now paying more and getting worse service, they'll be entitled to ask what exactly re-nationalisation was supposed to achieve.’

The figures, obtained by Mr Holden via written Parliamentary questions, show that the number of ‘short-formed services’ - where trains with fewer carriages than scheduled turn up - was 677 during the month before SWR was re-nationalised.

But this jumped to 1,026 during the month it was brought back into public ownership and was 848 the month after.

In June, Transport Secretary Heidi Alexander admitted in the Commons that SWR’s performance ‘has not been up to scratch’ and that she could not guarantee tickets would get cheaper amid growing complaints about poor service.

Labour came to power in 2024 promising to re-nationalise all of Britain’s 19 private train companies into a new state-run entity called Great British Railways (GBR).

Bringing the railways back into public ownership was a key demand of the party’s trade union backers, which want Labour to go even further by bringing more of the country’s transport network under public ownership, along with utilities and housing.

GBR-liveried trains are now starting to run around the rail network, including on the SWR network.

Greater Anglia, c2c, West Midlands Trains, Thameslink, Southern, West Midlands Railway and Great Northern have also since been re-nationalised.

Operator CrossCountry is set to be the last, scheduled to take place in Autumn 2027.

A Department for Transport spokesman said: ‘Passengers rightly expect enough space on board and we understand the frustration when trains operate with fewer carriages than planned.

‘Before public ownership, the number of SWR trains which were shorter than planned was rising due to its ageing fleet.

‘Public ownership has fixed that - unlocking the rollout of 53 new Arterio trains, with the number of short trains down by 26% year-on-year.’