It was the first top-level one-day competition to be introduced in English and Welsh cricket, amid concern about falling attendances at County Championship matches in the early 1960s.

The competition was based on the Midlands Counties Knockout Cup experiment of 1962, when Derbyshire, Leicestershire, Northamptonshire and Nottinghamshire played one-innings-a-side matches which each lasted one day.

The MCC decided to hold a limited-overs competition (65 overs-a-side) the following year for all first-class counties, sponsored by American safety razor company Gillette.

One of the most famous matches in the competition was the 1971 Gillette Cup semi-final at Old Trafford, with David Hughes of Lancashire coming out to bat at 8:45 pm (before any floodlights) and scoring 24 in one over to beat Gloucestershire.

[citation needed] There was a notable finish too in 1987 when Nottinghamshire's unlikely victory over Northamptonshire was engineered by Richard Hadlee in his last season with the county.

At a time when county cricketers' exposure on television was limited, the final of the Gillette Cup/NatWest Bank Trophy was a relatively high-profile opportunity for some to make a case for national selection, especially as it often fell in early September, just before the announcement of an England winter tour party.

[citation needed] The strong performances of then young cricketers Angus Fraser and Mark Ramprakash for Middlesex in 1988 certainly raised their profiles.

[7] Other notable individual performances included a brisk out-of-character century by Geoff Boycott in the 1965 final, and the domination of the 1979 final by the West Indies pair Viv Richards and Joel Garner, who helped Somerset to their first major trophy a few months after helping West Indies to win the World Cup, also at Lord's.

A rare exception occurred in 1996, when Lancashire bowlers Glen Chapple and Peter Martin triggered a remarkable collapse by Essex.

[10] In 1999, the number of overs was cut to 50 per side to give English and Welsh cricketers more experience of playing matches the same length as One Day Internationals.

The eighteen English and Welsh first-class sides, plus Scotland and Ireland, were split into two groups of ten by geographical location known as the North and South Conferences.