Analysis By James Landale Chief political correspondent, BBC News 24

The dilemma is: how hard to lay into your political opponent?

It is a truth universally acknowledged that nothing excites and delights an honourable member so much as the chance to place a well aimed, steel-capped boot into the nether regions of his or her political opponent.

However high-minded, however softly-spoken, however policy-driven, few politicians can resist the temptation to shove at least some leather into their rivals' fleshy bits.

The question, of course, is when should they put the boots on and how hard should they kick?

This is the dilemma that faces the Conservative Party as Labour struggles with the controversy over secret donations. Many Conservative MPs are having trouble disguising their glee at Labour's problems.

Many know exactly what it is like, having survived the final years of Conservative government under John Major in the 1990s.

They know how tough it is to get on with the business of government when your entire focus is on fighting fires day in day out.

If the Conservative leader goes in too hard, there is a risk voters will find him shrill and unsympathetic. No one likes a bully

Each week provides new rows and new revelations and all attempts to talk about policy or legislation disappear into the wind. For most ministers, the cliche of choice is that when it rains, it pours.

If you are a literary-minded Justice Secretary like Jack Straw, you quote Shakespeare's truism that sorrows come not as "single spies, but in battalions".

Cut out for the job?

So the Tories can be forgiven for experiencing more than a little schadenfreude. But how far should they put the boot in, now that it is, so to speak, on the other foot?

Well, so far, the Conservative leader, David Cameron, has not been shy at getting well shod.

Mr Cameron and Mr Brown at the Remembrance Sunday ceremony

At Prime Minister's Questions last Wednesday, he said Gordon Brown's explanation that he knew nothing about David Abrahams's secret donations "takes us to questions about the prime minister's own integrity". He pondered if Mr Brown was "cut out for the job".

On Thursday, Mr Cameron said the position of Mr Brown's chief fundraiser, Jon Mendelsohn was "indefensible" and he should resign. On Sunday, on the Andrew Marr show, he said Labour's position "beggars belief".

And he held a news conference to say that Labour was either "utterly dysfunctional or we are not being given the whole truth". So, Mr Cameron has not been reluctant to get stuck in.

His strategy is to help keep the "donorgate" issue in the public eye for as long as possible and avoid getting bogged down, as Labour wish, in the minutiae of party funding reform.

Poison the well

Yet there are dangers that some thoughtful Tories recognise. If the Conservative leader goes in too hard, there is a risk voters will find him shrill and unsympathetic. No one likes a bully.

Mr Cameron has worked hard to establish a reputation for being reasonable and personable and he will be reluctant to put that at risk. As the Daily Telegraph commentator, Janet Daley, said this morning: "Looking like the sadist of the lower-sixth egged on by a baying gang of henchmen is not consistent with his engaging New Conservative image."

Mr Cameron won't want to ruin his "engaging New Conservative image"

Furthermore, if the Tories attack too hard, they could establish a few hostages to fortune that might come back to haunt them.

Labour frequently criticise the Tories for the less than transparent financial support for the party that comes from Lord Ashcroft and groups like the Midlands Industrial Council.

On Monday morning Mr Cameron defended both but was more than ready to admit that all parties made mistakes, and that no one was perfect on this issue.

Perhaps the biggest long term risk is that the more the Tories put the boot in, the more they continue to poison the well of British politics, which is already pretty toxic. The risk is that voters will shout more loudly from the roof tops, "a plague on all your houses!".

So the Tories are looking to keep "donorgate" going, ask the right questions, and maintain the pressure on the government. But it is not a strategy without risk.