Holidaymakers are being warned that some popular Spanish islands are in danger of being moved to the amber list.

This means that anyone who travels to the islands may have to self-isolate for 10 days on their return to England.

The announcement comes only a fortnight after the Spanish islands were approved for quarantine-free travel.

The Balearic islands, including tourist hotspots Ibiza, Mallorca and Menorca, could be set to be moved off the green watchlist – destinations the Government considers safe for travel but which could potentially be downgraded to the amber list – on Wednesday due to rising cases, the reports have suggested.

Those travelling to amber listed countries, such as mainland Spain, have to self-isolate for 10 days on their return to England.

However, as of July 19 the requirement to quarantine will be scrapped for the fully vaccinated and those aged under 18.

The Sun, which first reported the alleged travel change, quoted a source saying: “It’s all still up for discussion, but the figures aren’t great which is why it was on the watch list in the first place.”

The Department for Transport said there was “nothing to say at the moment” on changes to the Balearic islands’ travel status.

Aside from countries potentially coming off the green list, some could be going the other way, according to an analyst.

Italy, Germany and Poland are among the destinations most likely to be added to the Government’s green travel list, Robert Boyle, former director of strategy at British Airways’ parent company IAG, has predicted.

He wrote on his website www.gridpoint.consulting that “strong candidates” from Europe to be added to the quarantine-free list also included Austria, Bulgaria, Latvia, Lithuania, Slovakia and Switzerland.

People arriving in the UK from green list destinations are not required to self-isolate.

North Wales Chronicle: Transport Secretary Grant Shapps is set to conduct broadcast interviews on Wednesday (Kirsty O’Connor/PA)Transport Secretary Grant Shapps is set to conduct broadcast interviews on Wednesday (Kirsty O’Connor/PA)

There is a case for Hong Kong and Taiwan to be shifted onto the green list as well, he added, while Canada was also looking a decent bet, although the North American country does not currently allow visitors from the UK.

The UK is battling its own summer spike in cases, with a further 36,660 lab-confirmed Covid-19 cases reported as of 9am on Tuesday.

Government data also recorded a further 50 people had died within 28 days of testing positive for coronavirus as of Tuesday – the highest day-on-day increase since April 9 – taking the country’s total to 128,481.

The Government’s travel lists are expected to be updated on Thursday, although reports have suggested it could come 24 hours earlier, with Transport Secretary Grant Shapps due to face the media on Wednesday morning.

Travel expert Mr Boyle also predicted Indonesia and Sierra Leone could be moved from the amber list to the red list, while Bahrain could go in the opposite direction because of “case rates plummeting”.

People arriving in the UK from a red-list location must spend 11 nights at a quarantine hotel, at a cost of £1,750 for solo travellers.

It comes as a couple were barred from making a trip to Malta due to having been given an Indian-made batch of the Oxford/AstraZeneca vaccine, according to The Daily Telegraph.

North Wales Chronicle: Daily confirmed cases of Covid-19 in the UK (PA Graphics)Daily confirmed cases of Covid-19 in the UK (PA Graphics)

Boris Johnson has recently looked to play down concerns that up to five million Britons could be barred from taking holidays in the European Union because their vaccinations are not recognised by its passport scheme.

The problem centres on doses made by the Serum Institute of India being known as Covishield.

Despite it being the same as other AstraZeneca vaccines, it has not been authorised by Europe’s regulator and is therefore not recognised by the EU.

The Prime Minister has previously stated he was “very confident” Covishield would not cause an issue, but Steve and Glenda Hardy, 64 and 63, told the newspaper they were turned back at Manchester airport at 3.30am on Friday when they tried to board a flight to Malta.

The Hull couple, who were given Indian manufactured doses of the AstraZeneca vaccine in March, said they had to holiday in Llandudno, Wales, instead.

It comes as First Minister Mark Drakeford prepares to set out on Wednesday whether coronavirus restrictions can be eased in Wales, which has the lowest Covid rates in the UK.

Mr Drakeford is due to confirm whether the delayed move to Alert Level One – which was pushed back by four weeks – can now take place, in a statement to the Welsh Parliament on Wednesday afternoon.

Meanwhile, a row over domestic travel regulations appeared to be brewing after London Mayor Sadiq Khan asked Transport for London (TfL) to enforce the use of mask wearing on buses and trains as a “condition of carriage”, even after legal restrictions to wear one are lifted next week.

Unions widely welcomed the Labour politician’s call, which looks likely to be taken up by TfL and used to put pressure on other transport providers, including mainline train operators, to follow suit.

Mick Lynch, general secretary of the Rail, Maritime and Transport (RMT) union, told PA news agency: “The train operating companies and the Government should be following this lead in the name of consistency, common sense and public safety.”