More than 35,000 have been left waiting longer than 10 weeks to receive a new passport, according to data from the Home Office.
The figures only cover the first three months of the year – January to the end of March 2022 – meaning many more UK travellers may have joined their ranks since then.
The number of full-time HM Passport office staff has also dropped by 681 over the past five years, according to the data, going from 3,913 to 3,232.
Many of these civil servants were replaced by agency staff.
Requested by Yvette Cooper, the shadow home secretary, the figures obtained fly in the face of Boris Johnson’s previous claims in parliament that Brits were receiving their travel documents within four to six weeks of submitting an application.
Ms Cooper said: “The Home Office is a shambles and ministers are totally failing to get a grip.
“Thousands of people have already had to wait more than 10 weeks for their passports, far too many passports are getting lost in the system and no one can get proper information out of the helpline.
“The government has failed to plan and badly mismanaged our services — this is the Tories’ Backlog Britain and it is letting families down.”
Louise Haigh, the shadow transport secretary, said the backlog was “causing misery for families”, saying, “These figures blow apart Boris Johnson’s nonsense claims.”
She added: “From processing passports to getting people through airports, this Tory government can’t even get the basics right.
“And now the Conservatives plan further senseless cuts, leaving staff fighting this huge backlog with one hand tied behind their back.”
It follows the story of a child having to miss out on his family holiday after waiting more than 12 weeks for his passport to be renewed.
Five-year-old Max Goodsir’s passport renewal was first submitted on 1 March 2022.
His mother, Victoria Richards, had planned a break to Cyprus for the whole family departing the following month on 3 April.
“I knew I was cutting it fine, applying to renew my children’s passports just five weeks before we were due to fly to Cyprus,” she tells The Independent.
“But it was a last-minute holiday, a last-minute decision. A spontaneous break away with their grandparents (my parents), who’d missed them terribly during the past two years of the pandemic.”
The passport failed to arrive in time, but on 5 April the status of the application was updated to “being processed”.
However, the six-week mark passed – the average processing time for renewals, according to the UK passport office – as did the 10-week mark, which is the generous amount of time travellers are currently advised to allow to receive their new passport.
After The Independent got in touch with HM Passport Office, a spokesperson confirmed that the application had been “approved” on 19 May and was finally printed on 23 May.
When asked why a straightforward five-year-old child’s passport renewal had taken so long to process, the spokesperson spoke of “checks” and “security”.