"The Labour Party do NOT have the right to try to form a government first. That right belongs to the Conservative Party,who have won both the most seats and the largest percentage of the vote."

That is an opinion but that is all it is. Convention is that Brown as incumbant has the right to attempt to form a govt. The problem for him is that Clegg isn't playing ball with that - and how could he after he's already expressed his opinion that the party with the most seats should go first? So Brown can't initially form a govt if the Lib Dems won't talk but that doesn't mean he does not have the right to attempt it. No doubt if Clegg can't work with the Tories he may then go back to Labour without losing face with the electorate over his comments so far.