DT Cryptic 25541

[Narbadingi]

Last one, and stumped.

21 ac. "Do not start to admit knave with film about school wear" -T-N -A-K-T

I assume the knave is a Jack, so it's probably 'something Jacket', but have no idea what the ?t?n is. Is there such a thing as an 'Eton Jacket', and if so how do you get that from the clue? Advice for a dimmie welcome. Ta.

[JMR27]

(L)Eton jacket

[Narbadingi]

Many thanks. Where does the film bit come in?

[Narbadingi]

Doh! E.T. - of course. Terribly slow, thanks.

[Tichfield]

ET was a film.

[michaelguy]

Narbadingi
This was the final clue for me as well.
To admit is "let"
Hence "do not start to admit" is "et"
Knave is jack (card game terminology)
Film is a "net"
So knave with film about is "njacket"
So far we have et?n jacket
I guess we fill in the last letter ourselves with an "o"
Therefore ETON JACKET

[factor-fiction]

Disagree slightly, Michaelguy. Crossowrd wouldn't expect you to add in a letter of your choice- the answer is always all in the clue.
Admit is LETON. So without the first letter it is ETON
Knave is a JACK
ET is a film

Hence ETONJACKET