The full squad, including five players from Heineken Cup finalists Leicester and Leinster, were due at the gathering at Pennyhill Park.

But the Lions were only informed this morning that Northampton, who tackle Bourgoin in Friday’s European Challenge Cup final, would not be releasing the Scotland prop.

“We are very disappointed and the Lions are talking to the RFU on this matter,” said manager Gerald Davies.

“We informed each union back in the autumn what our plans were for this week. At that stage no-one responded to say they disagreed with it.

“We did say we would like all the players available for Monday. We emphasised there would be no training and by 6pm the players involved in those competitions would be released back to their clubs and regions.”

Northampton’s decision was based on a ruling from the Premier Rugby board to stick by the clause that dictates clubs are not obliged to release players outside of a Test week.

A Premier Rugby spokesman said: “We have always been consistent that we won’t release outside of an IRB regulation nine period and Northampton have an important final this weekend, as do Leicester.”

However, Leicester’s Harry Ellis was made available by the Tigers to spend the afternoon at Pennyhill Park.