The group said the changes will leave “many students without a viable pathway” after finishing their GCSEs.
Earlier this year, the government announced reforms that it said would remove “low-quality qualifications that lack job prospects”.
It said apprenticeships, A-levels and new T-levels – two-year technical courses that are the equivalent of three A-levels – will become the main options for progression after GCSEs.
But Nadhim Zahawi, who was appointed education secretary last month, has been urged to reassess these plans by a cross-party group of 118 MPs and peers, including three former education secretaries.
“We are particularly concerned about the proposal to remove funding for the vast majority of BTECs,” the letter said.
“The plan for T-levels and A-levels to become the ‘qualifications of choice’ for most young people will leave many students without a viable pathway after their GCSEs, particularly those from disadvantaged backgrounds.”
The letter – signed by shadow education secretary Kate Green and the Liberal Democrat education spokesperson Daisy Cooper – added: “The Department for Education’s impact assessment concluded that these students had the most to lose from defunding BTECs. “
Lord Baker of Dorking, who was education secretary between 1986 and 1989 in Margaret Thatcher’s government, said the plans to scrap most Btecs “will be disastrous for young people and disastrous for employers”.
He added: “These qualifications are well established, well respected and help thousands of young people to enter higher education or the workplace each year.”
Bill Watkin from the Sixth Form Colleges Association said it was “telling that so many MPs and peers” had joined a “broad coalition of educational bodies”to support the Protect Student Choice campaign against the scrapping of Btecs.
“There are few issues that could engender such strength of feeling and such commonality of purpose; the removal of Btecs represents a hammer blow for social mobility, the skills gap and the economy,” he said.
Unions have previously called on the government to scrap the reforms, saying it would be “reckless” to scrap most Btecs and calling these qualifications “vital” in helping young people progress to the next stage in their lives.
The government has said the shake-up of the post-16 system will “reduce the number of poor-quality courses or duplication across the system”.
“Our reforms will simplify the current system and ensure young people can be confident that the qualifications they study will be fit for the future, high quality and lead to good outcomes,” a Department for Education spokesperson said.
“We have set out the qualifications we intend to fund alongside T Levels and A levels, and will fund Btecs or similar qualifications where there is a clear need for skills and knowledge that is not provided elsewhere.”
They added: “Employers are facing skills shortages that we must act to address. Now more than ever, it is vital that the qualifications on offer meet the needs of employers and support more people into higher skilled, higher wage jobs.”