Warren Gatland is poised to become the second man to head the Lions on major back-to-back tours. The head coach for the trip to New Zealand next year will be announced on 7 September and is expected to take an immediate sabbatical for 10 months.

Gatland was in charge in Australia three years ago when the Lions secured their first series triumph since 1997 when Ian McGeehan was head coach for the third tour in a row. McGeechan returned in 2009 when Gatland was one of his assistants and the series was lost 2-1.

The Lions had been due to announce Gatland as their coach in July after the end of the summer tours by the four home unions. Ireland’s Joe Schmidt and England’s Eddie Jones had ruled themselves out, but when Scotland’s Vern Cotter declared a late interest the appointment was put back. Cotter, a New Zealander like Gatland, has entered the last year of his three-year stint with Scotland, where the announcement will be made next month at the Edinburgh office of the Lions’ main sponsor, Standard Life. The location is not usually a clue: Gatland was unveiled as the head coach for the Australia tour in London in September 2012.

The issue of the sabbatical, which Gatland took before the Australia tour, although he was given permission to be involved the preparation for Wales’s match against New Zealand in November 2012, was a reason why the Rugby Football Union did not want Jones’s name to be put forward. The Australian has been with England for nine months, transforming them from World Cup laughing stock to Six Nations champions and 3-0 victors in Australia, and says his work has just started. Schmidt is in the last year of his contract which, unlike Gatland’s with Wales, does not contain a clause allowing him to take a sabbatical in a Lions year.

An issue for the Lions committee is that while Ireland won the grand slam in 2009 and Wales secured the Six Nations title in 2013 having secured the slam the year before, England are now the leading country in Europe, at international and club level. Much can change during a season, as Jones has shown, but his side are second in the world rankings with Wales fifth, one place above Ireland.

The 2009 and 2013 Lions squads had a total of 28 players from Wales, 23 from Ireland and 18 from England. Scotland supplied five and if that low figure were repeated next year it would give Cotter the advantage of relative neutrality. Wales and Ireland supplied 13 of the starting team in the deciding Test against the Wallabies and 11 in the opening match of the series against South Africa four years before.

Dylan Hartley has emerged as a rival to Sam Warburton for the captaincy, but with the Lions having so little time to prepare and with six matches before the first Test in Auckland, an element of familiarity would be an advantage.

If Jones is not involved in the tour, and it is unlikely he would want to be an assistant, one of his coaches, such as Steve Borthwick, would be an asset. The former England coach Andy Farrell, who is now with Ireland, was involved in 2013 and was commended for his work in the official tour report.

The head coach will choose his assistants for the toughest tour of all. Two of the three Tests will be played at Eden Park in Auckland, where the All Blacks have not lost in the professional era. The last time a home union tasted success against New Zealand was in 2012 when England won at Twickenham.

The Lions have won one series in New Zealand, in 1971, while the four home unions have defeated the All Blacks there twice, England in 1973 and 2003. The hosts have won 11 of the last 12 Tests against the tourists and Gatland’s Wales were whitewashed there in June, although they led at half-time in the first Test and were level at the mid-point in the second.

The Celtic nations have been warned that they are falling behind England and France at club level. Mark Dodson, the chief executive of the Scottish Rugby Union, told the BBC on the eve of the launch of the Guinness Pro 12 campaign: “The truth is that the French and the English have stolen a march and we understand that we have to look at ourselves.

“If we don’t do something with the Pro12, I think it’s a bleak prospect. We’re finding it very difficult to hang on to our top players. Even the people who aren’t leaving are demanding more. Unless we do something different we’re going to struggle.”