Conservative strategists are planning plenty of announcements for their conference - but they do not intend to make one on a European referendum.

That will surprise some, because as the party begins to gather in Manchester the Irish will announce the result of their referendum on the Lisbon Treaty.

If the treaty is rejected in Dublin the Conservative course is simple: they will go into the general election promising to hold their own vote on British ratification.

But if it is accepted by the Irish, things become trickier. A "yes" vote could mean the Lisbon Treaty is ratified by all member states by the time of the British general election.

If that were the case, the Conservative policy is not to let "matters rest there".

David Cameron has said: "If this treaty is still alive, if it is still being discussed and debated anywhere in Europe, then we will give you that referendum.

"We will name the date during the election campaign, we'll hold that referendum straight away and I will lead the campaign for a 'no'.

"Now, if those circumstances change, if the Germans ratify, if the Poles ratify, if the Czechs ratify, if the Irish vote yes to the treaty, then a new set of circumstances [apply] and I will address those at the time."

Pressure

So what would addressing those circumstances mean?

For the time being, the Tories refuse to say, and they do not plan to make themselves much clearer at their conference.

A Conservative spokesman confirmed their plan is to leave the "not letting matters rest" policy unchanged whatever happens in Dublin.

But the problem for the leadership is that some in the party have no intention of letting the topic rest.

They would like to see a referendum whether the Lisbon Treaty is ratified or not - and they will put pressure on their leaders to come to the same conclusion.

The last thing the Conservatives want at their conference is a public punch-up over Europe - the subject has proved toxic for the party in the past.

But they could yet find some salvation in a Prague courtroom.

Czech senators have referred a complaint about the treaty to the country's constitutional court, which will slow up the ratification process by weeks, possibly months.

That delay could be enough to put off the issue until after the Tory conference at least, especially as the Polish president has also yet to ratify the treaty.

Beyond that there are ideas for a compromise. The Euro-sceptic think tank Open Europe has suggested if the treaty was ratified the Tories could announce a referendum on a package of EU reforms.

It is hosting the Conservative shadow Europe minister, Mark Francois, at a conference fringe event where he will be in discussion with one of the party's best known MEPs - Daniel Hannan - who would like to see Britain withdraw from the EU.

So, whatever the Irish decide, and whatever Conservative HQ intends, there will be lots of talk about Europe at the party conference.

Expect to hear much on "not letting matters rest", both from the leaders and the grassroots.