Scotland scrum-half Greig Laidlaw and fly-half Finn Russell have already been put on the 'reserve list' to join the British and Irish Lions tour of New Zealand.

Sportsmail can reveal that both are first in line to be called up if any player in their position is injured, with a senior Lions source describing Laidlaw as 'the unluckiest player' to miss out on selection of all those considered.

Conor Murray of Ireland and Rhys Webb of Wales were always going to be picked at No 9, leaving Lions head coach Warren Gatland and his selection panel to choose between Scotland skipper Laidlaw and England's Ben Youngs for the third scrum-half spot.

Scotland scrum-half Greig Laidlaw and Finn Russell are on call for the British & Irish Lions

Glasgow Warriors star Russell will be called up ahead of others if there are injuries at No 10

Because Laidlaw hadn't played since picking up a knee injury in the Six Nations defeat to France and Youngs had been part of the England team that won the tournament, the Gloucester man missed out on joining Stuart Hogg and Tommy Seymour in the 41-man squad.

'If Greig Laidlaw had been fit when we selected the squad and played more in the Six Nations he would have gone to New Zealand ahead of Ben Youngs,' said the Lions source.

'He showed himself up to be a real leader with Scotland, is a very good goal-kicker and has great game management. Even with him injured he still came close to selection and the decision to take him or Youngs was one of the tightest, if not the tightest we had to make. In the end Youngs had played more in the Six Nations.'

Johnny Sexton of Ireland and England's Owen Farrell, who can also play at centre, were certainties to be picked at fly-half, which meant the selectors had to choose from Dan Biggar of Wales, George Ford of England and Russell for the third place.

George Ford was overlooked by Warren Gatland and Russell is seen as the next fly-half option

Biggar got the nod narrowly ahead of Russell, but the Glasgow Warriors star will be called up ahead of Ford if there are injuries at No 10.

Both Laidlaw and Russell will be in close proximity to the Lions, as they will be touring with Scotland in the southern hemisphere when the gruelling ten-match tour, which includes three Test matches against the All Blacks, is taking place.

Scotland play Italy in Singapore, Australia in Sydney and Fiji in Suva which will make it easier for them to link up with Gatland's squad if required.

Knowing he was so close to Lions selection will be a boost to Laidlaw, who only made his comeback off the bench for Gloucester in their European Challenge Cup semi-final win over La Rochelle last weekend. He is now looking forward to featuring in the final against Stade Francais at Murrayfield on Friday May 12.

Laidlaw only made his comeback for Gloucester in the European Challenge Cup last weekend

Laidlaw, who spent eight seasons at Edinburgh Rugby, said: 'The physio and strength and conditioning teams have worked really hard to get me to this place and back playing.

'I felt good in the semi-final and will continue to work on getting my sharpness back. I'm feeling better every day. It's just about fine tuning now.

'It would be brilliant to finish my Gloucester career before I join Clermont in the summer on a high by winning the European Challenge Cup final in Edinburgh.

'I love playing at Murrayfield for Scotland and the recent win over Ireland was one of my most memorable games in the Scotland shirt. Hopefully, with the Scottish connection to Gloucester through me and many other Scotland players like Matt Scott, we'll have the backing of the Scottish support as well in the final against Stade Francais.'