Around 3,000 asylum seekers could be living on a barge and in former military sites by the autumn in a Government bid to cut back on using hotels.

Around 500 migrants will be housed on the Bibby Stockholm barge – which was met with protests when it arrived in Portland earlier this week – while the rest are set to be given accommodation at Wethersfield in Essex and Scampton in Lincolnshire, the Home Office said.

But when the first group of asylum seekers will take up residence on the barge has been thrown into doubt, with officials unclear on an exact timescale.

Earlier this week, the Home Office said around 50 people would arrive “from next week”, with numbers gradually rising over the coming months.

Facing questions from reporters on Friday, officials refused to specify a date or confirm if there had been any further delays to the plans, instead insisting the arrivals would be in the coming weeks.

The Bibby barge arrived in the Dorset port a month behind schedule after maintenance work – which included mechanical repairs and adding more beds to boost capacity – was carried out in Falmouth, Cornwall.

With an initial 18-month contract for the barge being kept under review, asylum seekers will spend up to nine months on board. But officials admitted they could end up back in hotels if no other suitable alternative accommodation was identified by the end of that time period.

During a press tour of the vessel, officials also remained tight-lipped on the daily running cost of the barge but stressed it was “significantly” cheaper than the £6 million-a-day taxpayer bill of using hotels.

Asked about the cost, Home Office deputy director for asylum accommodation Leanne Palk said figures would not be revealed until they are published in end-of-financial year accounts, adding: “This is significantly cheaper than a hotel.

“We have very rigorous tests on value for money and they do provide value for money against the cost of hotels.”

Single men will live on the barge – where there is 24-hour security – in bunk beds with between two and six people per en-suite room.

A canteen, gym, classroom, exercise yards, television room and space for worship are among the “basic” facilities on board.

A nurse will also be stationed on the barge five days a week, with asylum seekers having access to a doctor if needed.

Ms Palk dismissed claims from campaigners that the barge was a “floating prison” and said people on board would be “free to come and go as they want”.

The inhabitants do not have a curfew but are expected to sleep aboard overnight.

They will be able to use an hourly bus service with stops in the surrounding area between 7am and 11pm, with migrants also free to leave on foot if they choose once outside the port compound. But inside the perimeter, they must board a shuttle bus to be taken from the barge to the gate because of safety rules inside the working port.

Dorset Council is receiving £3,500 per occupied bedspace on the Bibby Stockholm, with additional funding provided to local NHS services and police, the Home Office said.

It is understood the council has also received almost £380,000 in a one-off grant to help support local charity and voluntary organisations provide services on board.

Last week, the Home Office announced the first asylum seekers had moved to a disused airfield at Wethersfield.

But Braintree District Council and a nearby resident are bringing legal action to challenge the decision to house up to 1,700 men there.

Home Secretary Suella Braverman’s plans to house up to 2,000 men at former airbase RAF Scampton in Lincolnshire, with initially 200 people arriving at the site, are also facing a similar challenge from West Lindsey District Council.

The Home Office said it is still working on developing the site and is yet to confirm when it will open.

It comes as the number of migrants who have arrived in the UK after crossing the Channel so far this year topped 14,000.

Some 291 people were detected making the journey in five boats on Thursday, taking the provisional total for 2023 to 14,362.

Meanwhile, the Government’s sweeping asylum reforms became law as the Illegal Migration Bill became an Act of Parliament after being given royal assent.

The much-criticised flagship legislation, central to the Prime Minister’s pledge to “stop the boats” crossing the Channel, will prevent people from claiming asylum in the UK if they arrive through unauthorised means.

Crossings continued on Friday, with children among the arrivals pictured being brought to shore in Dover, Kent.

Officials are still working on when the Act will come into force and it is anticipated elements of the new laws may be implemented in stages over the coming months.

Immigration minister Robert Jenrick said: “This Government has been clear that those who arrive in the UK illegally should not be housed in expensive hotels.

“Our use of alternative accommodation sites and vessels provide basic and appropriate standards for small boats arrivals while their claims are determined.”