Sussex’s hopes of making an instant return to division one of the County Championship have been dealt a blow.

The ECB has announced that only the winners of division two will be promoted this season as part of a restructuring of the domestic game.

The move will see division one reduced to eight teams from 2017 – when the Championship will revert to two up, two down – with division two made up of ten counties.

A reduction in the number of games from 16 to 14 will anger traditionalists but a switch to Big Bash style franchise Twenty20 competition has been avoided.

Instead the NatWest T20 Blast will continue in its current format although it will now be played in two blocks in July and August – in a bid to take advantage of the summer holidays - rather than on Friday nights throughout the summer.

The Royal London One-Day Cup will be moved to a block in April and May with group winners qualifying for the quarter-finals while second and third placed teams enter the quarter-finals.

Tom Harrison, ECB chief executive, said: “These are sound decisions reached through constructive discussion. It’s important that everyone was aware before the start of this season how things will work next year.

“For 2017, an early-season block for the Royal London One-Day Cup will let county players focus on the white-ball game and support England’s preparation for the ICC Champions Trophy here.

“NatWest T20 Blast will start later in the summer, when more children and parents are on holiday and can come along, helping to attract new fans and inspire more people to play and attend. The County Championship remains the bedrock of the summer, from April to September."

Harrison also hinted there is likely to be further changes from 2019 when the current television deal with Sky comes to an end – with the introduction of a city-based franchise Twenty20 competition likely to be high on the agenda.

Harrison added: “We now have a great opportunity to take a detailed look at a range of options and find the best structure for the long-term health of the domestic and international game.”