Part knife bayonet and part socket bayonet, The No. 7 was a very innovative and complex design, with a unique swiveling pommel. The No. 7 Mk. I/L (spoken: number seven, mark one, land service) was intended to address a number of desires:

1) Replace the No. 4 spike bayonet (that nobody liked);
2) Utilize the clip-point blade of the No. 5 Mk. I bayonet (that everybody liked); and,
3) Serve a dual role as a fighting knife.

Despite all of it's ingenuity, the No. 7 Mk. I/L came to prove the old adage that a camel is a horse, as designed by committee. It was also capable of mounting to the Lee-Enfield No. 4 rifle, these bayonets were not issued as such, only being used with the No. 4 rifle for ceremonial purposes.

The grip scales are made of a resin impregnated cloth composite, Paxolin, and have deep finger grooves to allow use as a fighting knife. Examples are also found with black grips.

176,000 No. 7 Mk. I/L bayonets were produced. The design was perfected by the Wilkinson Sword Co., who produced 1,000 bayonets in 1944. Mass production was carried out by four manufacturers from 1945–1948:

Birmingham Small Arms, Ltd. —25,000;

Elkington & Co. Ltd., Birmingham —20,000;

Royal Ordnance Factory, Poole —30,000; and,

Royal Ordnance Factory, Newport —100,000.