Analysis By Nick Assinder BBC News Online political correspondent

Howard knows he has a struggle

And, as Michael Howard's honeymoon period appears to have come to an end with a bump, they are at it again.

Mr Howard certainly has his troubles. In the final couple of weeks of the current parliamentary session he watched his party plunged into a humiliating third place in two by-elections.

He notably failed to nail Tony Blair in the debate over the Butler report on Iraq.

And all this came against a background of stubbornly depressing poll showings and the fact that the prime minister seems to have got the measure of him in their weekly question time sessions.

So, while Mr Blair set off on holiday with a huge grin on his face - believing he has come through the worst - Mr Howard has got the old voices of dissent ringing in his ears.

Horribly familiar

Former party chairman Lord Norman Tebbit has offered up his now traditional advice that the only way for the Tories to win is to shift onto an unapologetically right-wing, Thatcherite agenda.

Ex-ministers Michael Portillo and Lord Michael Heseltine, however, have weighed in insisting that is precisely the last thing Mr Howard should do.

Tebbit wants Thatcherite agenda

Losing London mayoral candidate Steven Norris has put his oar in, saying the party needs to raise its game.

And even ex-leader Iain Duncan Smith is reported to have said privately the party is in no better shape than when he was in charge - although he denies criticising Mr Howard.

Nevertheless, this probably all sounds horribly familiar to Mr Howard.

It is exactly the sort of internal sniping between left and right, "mods and rockers", that ultimately led to the demise of Mr Duncan Smith.

And, once people start indulging in it, it proves extremely difficult to stop. Even pleas for silence actually serve only to add to the atmosphere of wobble.

Civil war

But there are major differences between now and what went before - enough to ensure the opposition leader is secure until after the next general election at the very least.

Indeed, if there is any positioning going on in the party it is only with the plotters' eyes focused on post-election scenarios.

The biggest difference now, of course, is that Michael Howard is not Iain Duncan Smith.

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He may not be the most charismatic leader on the planet, but he is way ahead of IDS in that department.

But he has also pulled off a number of the tricks that had been glaringly necessary for years.

And by far the most impressive and important was the way the party rallied around his leadership and appeared to accept the civil war had to stop if they were to look anything like a general election threat.

Some of that discipline may have eroded, but there are no signs it is about to break down completely.

Protest vote

Similarly, the less panic-ridden and the non-plotters know that by-elections can mean nothing when it comes to the general election.

When that day arrives, voters will be deciding whether they want to kick out the government. If they do, they will probably accept, no matter how reluctantly, that only the Tories can do that.

If they do not, then Tony Blair remains in power and the worst he can expect is to see a large chunk of his support going to an array of third parties.

The Liberal Democrats may do extremely well from that. But it is very likely still a protest vote rather than a vote for an alternative government - although that could change one day.

Mr Howard must know he still has work to do and he still has an electoral mountain to climb.

But he will also be reminding his party of the reasons they backed him in the first place - and they still apply.