Avro 691 Lancastrian.
Inboard engines are Merlin T.24/2, outboard engines are Rolls Royce Nene turbojets.
Once airborne, the Merlins would be shut down, and it was flown using only the Nenes. A back door way of claiming to be the world's first commercial aircraft to fly solely on jet engine power.
My regards,
Widewing