I read this recently and didn't take it seriously but listening to the Tory spokesscum being interviewed on the Beeb, they are clearly laying the foundations for just such a power-grab.
From liberalconspiracy.org:
"Despite accusations of Conservative complacency in the run up to Thursday’s General Election, a great deal of effort has gone into what happens if the result is not a clear cut one but results in a Hung Parliament with the Tories some way short of an overall majority.
Here is what has now emerged as the Tory plan:
• Declare victory anyway.
• Have the party’s media allies strain every sinew to make that a self-fulfilling prophecy.
• Insist on being given the keys to number 10 without having to talk substantively to any other party first – to avoid a coalition or any substantive policy concessions.
• Make a partisan challenge to the civil service in seeking to overturn any existing constitutional convention or practice that might conceivably get in the way, or even slow this down a little.
• Threaten to drag the Monarchy into political controversy for partisan advantage, by challenging the conventions designed precisely to avoid this.
• Hold out against electoral reform, whatever the election result.
• Threaten apocalyptic political and financial meltdown if anybody disagrees.
The key objective of this strategy is to use the vociferous campaigning of the press – no doubt amplifying interventions from friends in the City – to argue that any negotiations between parties would be democratically illegitimate, without first putting the Conservatives into power, even (or especially) if Labour and the Liberal Democrats could between them muster a majority of both votes and Commons seats.
See David Cameron’s interview with Monday’s Independent – in which the Tory leader says “there is convention and there is practice and they are not always quite the same thing”.
The rest is here:
http://liberalconspiracy.org/2010/05/04/this-is-how-the-tories-plan-to-seize-power-in-a-hung-parliament/I'm honestly not sure how such a power-grab could be prevented, given that HRH has virtually no power and our media is dominated by the right-wing.