Eleven months after the grandest of Grand Slams comes the slamming of the door - a sound that will have the whole of Welsh rugby quaking at its very foundations. Mike Ruddock, the former Swansea flanker who coached the Red Dragonhood to a first international championship clean sweep in more than a quarter of a century, stood down from the job last night citing family reasons.

The word on the street suggested those reasons had more to do with a collapse in relations with his players.

Steve Lewis, the recently appointed chief executive of the Welsh Rugby Union, confirmed Ruddock's departure after several hours of gathering rumour and speculation. Ruddock told him that he would not be seeking to renew his contract at the end of the current Six Nations Championship, and after further discussions, it was agreed he should walk away without further ado. Scott Johnson, the popular Australian who has effectively been second in command, will run the show for the remainder of the tournament.

"It is quite clear that the pressures of the job were too much for Mike, that they were inconsistent with other things happening in his life," said Lewis, who emphasised that there was no contractual dispute with the coach. For his part, the WRU chairman, David Pickering, said: "We have been put in a position of crisis because of a crisis affecting one individual."

This is the second high-profile departure from the WRU in the space of a couple of months. David Moffett, the man lauded by some as the saviour of the Welsh game and by others as its destroyer, ended a controversial stint as chief executive shortly before Christmas, having downgraded club rugby to semi-professional status, railroaded regional rugby into being and then cut the number of those regions from five to four in the face of opposition from disenfranchised rugby supporters in such traditional union strongholds as Pontypridd and Bridgend.

Yet under Moffett and Ruddock, who succeeded the New Zealander Steve Hansen at the end of the 2004 championship, Wales scaled their greatest heights in 27 years by winning all five of their Six Nations games last season. They played an attacking brand of rugby that both thrilled the diehards and captured the imagination of a new generation of union followers. Ruddock received an OBE for his trouble. If the Welsh population at large had had their way, he would have been canonised.

There were, however, whispers of internal upheavals even while Wales were producing performances shot through with flair and adventure. While Lewis went out of his way to play down suggestions of a split between Ruddock and his players, there were well-publicised internal stresses and strains ahead of last weekend's match with Scotland at the Millennium Stadium.

"This has been a tough decision to make, but I have decided to put my family first," Ruddock said last night. "I have found during my two years as coach that this position is more than a job. I have spent long periods away from my family, in camp and on overseas tours. As a consequence, I felt the intense build-up to next year's World Cup would mean more time away from my family. That is something which, on reflection, I would like to avoid."

The news travelled to every corner of the Welsh game with lightning speed, and shocked those corners to their core. The former national captain Ieuan Evans suggested that there was more to Ruddock's departure than family pressures, saying: "It's strange and it's baffling. We are not quite sure of the reasons behind it. Was he unhappy? Was the union unhappy about something that has happened? Obviously there are issues behind this. Whatever the reasons, he has empowered the players, which is a big step ­ the foundation was laid by Hansen, who got the basics right, but Mike Ruddock has given the players the freedom to express themselves."

Moffett, one of those most heavily involved in the appointment of Ruddock, said: "The job of coaching is a particularly difficult one, because you are never out of the goldfish bowl and it does affect your family life. Mike is a big family man, always has been, and I can understand and respect his decision. It's a shame, though. Rugby in Wales is a roller-coaster, there is no middle ground. It's either euphoria or despair, and being part of that roller-coaster can take its toll."

Lyn Jones, the head coach of the Ospreys, feared for Wales' World Cup chances. He said: "Things seemed to be going according to plan, but it looks like we are going to take another U-turn. There has been a big feel-good factor over the last two years in Wales. We are all surprised at what is going on. I can't quite believe it."

The Ruddock file

THE PLAYER

Played in the back row for Blaina, Tredegar and Swansea, making 119 appearances in all and scoring 43 tries. Selected for Wales Under-21s and Wales B but suffered three compressed vertebrae and a fractured skull in an accident at work in 1985 and was forced to retire from playing aged 26.

THE COACH

After spells at Blaina, Cross Keys and Bective Rangers, Ruddock took over at his former club Swansea in 1991. He moved to Ireland as director of coaching at Leinster, and took charge of Ireland A, before returning to Wales with Ebbw Vale in 2000. After a year with Newport Gwent Dragons he succeeded Steve Hansen as coach of the national side in 2004.

THE HONOURS

Coached Swansea to the Welsh league title in 1992 and 1994, and the Welsh Cup the following year. His side also beat the touring Australians 21-6 in 1992.

As Wales coach, he led his country to their first Grand Slam title since 1978 with victory over Ireland in 2005 and, last autumn, a first win over Australia in 18 years. He was awarded an OBE in the 2006 New Years Honours.

THE RECORD

Wales: P20 W13 D0 L7