Subsequently, Germany and UK started discussions and design studies and in 1968 established agreed operational characteristics for a towed 155 mm close support gun.

The UK Royal Armament Research and Development Establishment (RARDE) was responsible for designing the HE projectile and the charge system.

Germany was responsible for Smoke, Illuminating, Minelet and extended range HE, although the development of the last two was not completed in the programme.

[3] FH70 features included: The barrel was 39 calibres long, giving 827 m/s standard maximum muzzle velocity.

All this meant that the gun could be operated by a minimum detachment of only four men (commander, layer and two loaders).

1st Regiment RHA, a unit that had conducted the Troop trials, developed their own procedures to solve these problems, related to dust contamination, and this process became established in official manuals in due course.

In the UK's case, this led to the Unit Load Container carrying 17 complete rounds, including shells with fuzes fitted - a novelty for 155 mm.