That is the warning from the Federation of Master Builders after plans for the practical alternative to A Levels were confirmed this week.
The first schools and colleges to teach the new technical qualifications will offer courses from 2020 with construction among the first subjects.
FMB Chief Eexecutive Brian Berry said: “The idea that a student who has completed a T Level in bricklaying is able to call themselves a qualified bricklayer is not credible.
“The Government must be realistic about how much can be achieved in two years of largely college-based learning.
“Although T Levels include a three-month work placement, when the rest of the individual’s knowledge and skills are acquired in the classroom, in construction they will need more time onsite, post-T Level, before they can and should describe themselves as being qualified in that trade.
“Small and medium-sized construction firms, which do the bulk of training in our industry, would rather view T Levels as a rich pool of talent through which to find apprentices.”
Berry added: “More positively, the Government has listened to the concerns of the construction industry and stated its intention to make work placements as flexible as possible.
“In construction, work placements are not popular or common so persuading sufficient numbers of employers to offer these opportunities will be challenging.
“The Government being open to the three-month placement being achieved through more than one employer is therefore vital.
“However, to ensure work placements are as attractive as possible, the Construction Industry Training Board should consider offering financial incentives to employers through CITB Grant.
“We know, for example, that a typical construction SME is likely to shell out an additional £500 for their Employers’ Liability insurance because of having a young person onsite for three months.
“This is on top of the resource needed to closely supervise that young person. If employers can be financially incentivised somehow, it would be helpful.
“If implemented properly, T Levels have the potential to provide parity of esteem between vocational and academic education.
“Although there are challenges regarding the implementation of T Levels, we are committed to working with the Government constructively to overcome those challenges.”