New flexible rail season tickets will disappoint passengers and fail to bring them back to the railway, passenger groups and campaigners have said as the tickets went on sale in England on Monday.

The government scheme is designed to make rail travel cheaper for part-time workers, with more splitting their time between the home and office since the coronavirus pandemic.

However, the new tickets, part of a wider shake-up of the rail industry, were criticised by campaigners and commuters for offering paltry savings as the prices were revealed.

Alice Ridley, of Campaign for Better Transport, said: “Many passengers are going to be disappointed. There’s a danger that people will change the way they commute and start driving, and we wanted flexible tickets to encourage people back onboard trains. We don’t think these tickets are going to do that or provide the savings that people had hoped for.”

She said there appeared to be no standard level of discount and the savings were not comparable with those made by passengers commuting full-time.

London TravelWatch said the fares were disappointing but the changes were “a step forward, although the jury is still out on whether the savings will be enough to entice people back to the train”.

The government said flexible season tickets, which can be used from 28 June and give unlimited travel between two stations on any eight days in a 28-day period, would save part-time commuters travelling during peak hours at least 20% on a monthly season ticket. The government has estimated passengers could save up to £350 a year.

However, the cost for each flexi ticket journey on many routes appeared to be more than doublethat of a full-time season ticket, making their value questionable.

On many lines, commuters would only make any savings compared with a walk-up ticket if they travel at peak times for all eight days a month, according to the season ticket calculator on the National Rail website.

A Brighton-London flexi ticket for eight days’ travel in a 28-day period works out at £39.90 a day, compared with £16.61 a day for a full-time season ticket, with a walk-up anytime return single normally costing £45.50.

Fares on some routes, including between Liverpool, Manchester and Leeds, were either unavailable or yet to be fixed.

Some anomalies were apparent: the new flexi fare appeared to be more expensive than a daily anytime return on at least one route, with Brighton-East Croydon costing more than £30 a day on a eight-day flexi season ticket, compared with a peak anytime return of £27.20.

The Department for Transport said the flexi season tickets would match “modern working habits and save passengers hundreds of pounds”.

“As we kickstart the biggest reforms to our railways in a generation, flexible season tickets are the first step,” said the transport secretary, Grant Shapps. “They give us greater freedom and choice about how we travel, simpler ticketing and a fairer fare.”

The scheme is part of a long-awaited overhaul of the rail industry announced last month. The Williams-Shapps plan for rail revealed that a new-state owned body – Great British Railways – would take over timetables, prices, ticket sales across England and managing rail infrastructure.

While most services will still be run by private companies, they will no longer operate franchises but hold contracts that incentivise them to run trains more efficiently and on time. The plan also aims to streamline and simplify fares, including extending contactless and pay-as-you-go systems to more parts of the country.