THE SNP have been warned not to play "political games" over the Ministry of Defence's intention to reserve direct control over Crown Estate land in Scotland that is used for key military purposes.

But the SNP hit back at the claims by Defence Secretary Michael Fallon, accusing David Cameron's Government of "completely abandoning" any idea of living up to last year's cross-party deal on extra powers.

The Crown Estate covers vast tracts of land in Scotland such as the seabed, large rural estates and half the coastline.

It also includes land around the Faslane nuclear submarine base, military training camps and firing ranges such as Cape Wrath in the far north west tip of the country.

On Monday, MPs are due to debate the devolution of the Crown Estate to the Scottish Parliament as they further scrutinise the Scotland Bill.

However, Michael Fallon, the Defence Secretary, is adamant that for the protection of the UK, the integrity of its defence capability and the professionalism of the armed forces, the MoD has to have reserve protection of certain Crown Estate land.

During the Smith Commission process, the UK Government was keen to stress the importance of Crown Estate land in preserving Britain's commitment to Nato and SNP sources noted at the time how Whitehall had sought to include a "carve-out" for defence when devolving Crown Estate assets.

The MoD has been subsequently keen to stress that the Commission report concluded that the cross-party agreement "should not be detrimental to matters of defence and security".

The Secretary of State claimed political posturing by the Nationalists would not get in the way of maintaining reserve protection of MoD assets.

Mr Fallon said: "We cannot compromise the integrity of our defence, including the deterrent, by allowing the SNP to play political games.

"The only purpose of reserving this control over defence sites is to ensure that any future development is fully compatible with the way in which we operate our training and other defence activities in Scotland," he added.

He stressed that there would be an agreement drawn up with the Scottish Government about how the creation of any future developments would work so that the operation of MoD facilities would be safeguarded.

But he added that it was key that the power over the Crown Estate used by the armed forces was a reserved one because the defence of the realm as a whole was reserved to Westminster and it was important that Britain's nuclear deterrent continued as it had done for the last 50 years.

UK Ministers are keen, in devolving most Crown Estate land, to see greater commercial enterprise to benefit local communities but, equally, they are concerned that in the years ahead land used by the MoD could be compromised if, without having the reserve control, Edinburgh, as the planning authority, decided to allow the building of a marine conservation area or some new infrastructure next to Faslane or a firing range, that could compromise military assets, which are essential to help guard against current and future threats.

Angus Robertson, the SNP leader at Westminster, said: "Michael Fallon does his case no favours with this kind of language.

"It is increasingly clear that the Tories have completely abandoned any idea of living up to the Smith Commission or recognising the mandate from the people of Scotland that the SNP received in May - so to suggest we are ones playing games is ridiculous.

"It is this Westminster government that is playing fast and loose with what they promised - what they pledged last year - and are now turning their backs on. Trident is an obscenity - a total waste of money at any time but during a long period of Westminster austerity even more indefensible. Mr Fallon needs to stop being so high handed and dismissive of people's concerns - or he will damage even further the union he professes to support