If, as expected, the Irish, English, Welsh and Scottish rugby unions join forces to bid for the 2015 Rugby World Cup they will face competition from four other Unions as a record number of countries are set to make official bids to host the event.

Although the Welsh Rugby Union had been considering a joint tender with England, it is understood the preferred route is to join forces with the Irish, Scottish and English Unions in a combined bid.

Italy, South Africa, Australia and Japan have all confirmed they will also tender for the 2015 event.

Eight countries have also expressed interest in the 2019 tournament — Ireland, Scotland, Wales, Italy, South Africa, Australia, Japan and Russia.

Each union had six weeks to review in detail the Rugby World Cup tender document before formally expressing their intention to tender.

International Rugby Board chairman Bernard Lapasset said: "This strong response is unprecedented, and truly reflects the global attraction of the Rugby World Cup.

"It also reflects the significant economic benefits that accompany the hosting of a tournament that has grown in stature and prominence as a global event.

"For the first time, the IRB will award two tournaments at the same time. This provides longer-term certainty for the hosts, Rugby World Cup Limited (RWCL) and the tournament's commercial partners.

"It also ensures that future development investment initiatives in the game worldwide can continue to be underwritten by the tournament and planned accordingly. The IRB Council will announce the RWC 2015 and 2019 host unions in July 2009, six years prior to the first tournament and 10 years prior to the 2019 event.

"This timetable reflects the scale and nature of the preparatory work in delivering this world-class tournament."

The 10 unions now have until May 8th next year to submit their detailed tender responses, before making formal presentations to IRB chiefs.

The next tournament — in 2011 — will be held in New Zealand.