Britain is in danger of putting at risk the fight against terrorism and organised crime if the Conservatives win a battle within the coalition to end British involvement in a series of European Union justice measures.

As Downing Street rushed forward David Cameron's long-awaited speech on Europe, which he will now deliver in the Netherlands on Friday, key crime fighting agencies warned of a risk to public safety if Britain distances itself from the EU.

The prime minister will move to heal divisions within the Conservative party over Europe, which played a part in the overthrow of Margaret Thatcher in 1990, when he sets out plans on Friday to hold a referendum on British membership of the EU.

Downing Street was forced to bring forward the speech by four days after France and Germany reacted angrily to reports that it would take place on 22 January. Angela Merkel is understood to have told Cameron of unease that the speech would take place as Paris and Berlin celebrate the 50th anniversary of the Elysée treaty which set the seal on their postwar reconciliation.

In his speech, delayed by months amid Tory divisions and concerns on the continent that Britain is moving to the exit, the prime minister is expected to say he will seek consent in his party's manifesto for the next election to renegotiate the terms of Britain's EU membership. He will brief Tory cabinet ministers at a special political cabinet on Wednesday.

He would use an expected revision of the Lisbon treaty within the next five years, designed to underpin new governance arrangements for the eurozone, to repatriate powers to Britain. The changes, which could involve radically rewriting the working time directive and safeguarding British interests in the single market as the eurozone integrates, would then be put to the British people in a referendum if the Tories win the next election.

Coalition divisions will be highlighted when Nick Clegg, who has described Cameron's plans to repatriate powers as a "false promise wrapped in a union jack", embarks on a series of early morning broadcast interviews.

The challenge to the prime minister of reframing Britain's position within the EU has been highlighted by a series of warnings of the dangers of abandoning EU justice measures. The prime minister has agreed with Clegg that Britain will exercise its right under the Lisbon treaty to opt out of around 130 criminal justice measures by next year.

But the two leaders are involved in an intense debate as the prime minister argues that Britain should then opt back in to a minimal number of measures. Clegg has said that the police and MI5, which want to retain measures such as the European arrest warrant (EAW), should be given the final say.

The Association of Chief Police Officers has issued a powerful warning of the dangers of opting out of the EAW and other measures. In a submission to a House of Lords EU subcommittee, it said: "Most of the stakeholders consulted believe that opting out of this and relying on alternative arrangements would result in fewer extraditions, longer delays, higher costs, more offenders evading justice and increased risk to public safety."

The association cited two case studies to show the importance of the arrest warrant. It said Hussain Osman was found guilty of conspiracy to murder for the failed tube bomb attack on 21 July 2005 after being extradited within two months under the EAW. In contrast it took France 10 years to extradite Rachid Ramda from Britain after being arrested in Britain in connection with a 1995 attack on the Paris transport system. He was eventually sentenced in France in 2006.

David Anderson QC, the independent reviewer of terrorism legislation, told the Lords committee: "My only concerns as independent reviewer are that the UK should not put at risk its ability to rely on such pre-Lisbon measures as are of genuine assistance in the fight against terrorism and, more broadly, that it should not diminish the beneficial influence over other countries' approach to counter-terrorism that it has earned through the EU over the years."

The Irish government has raised concerns about the impact of tackling cross-border terrorism. In his submission to the committee, the Northern Ireland justice minister, David Ford, said that Ireland's justice and equality minister, Alan Shatter, has raised concerns. Ford said: "I remain concerned that the potentially very significant effects on Northern Ireland may not be fully recognised in Whitehall. It is vital that the decisions made are those in the best interests of all parts of the UK."

Downing Street has said it will do nothing to jeopardise public safety. Sources said No 10 was relaxed about the delay in the prime minister's speech despite anger in the Tory party that it has allowed critics, from supporters of the German chancellor, Angela Merkel, to the former deputy prime minister Michael Heseltine to attack the prime minister.

One source said: "We are supremely relaxed. This is such an important issue that a debate must take place. The debate has always been framed in a eurosceptic way. It is good that the sleeping giants of europhilia have come out."

A No 10 spokesperson said: "We've made clear that we will decide what to opt back in to on a case by case basis, guided by what is in our national interest and how best to ensure our national security and public safety."

The prime minister is expected to depict himself as a practical eurosceptic in his speech who wants Britain to remain in the EU, though not on its current terms. Sources said it is impossible to see a new treaty, supporting new arrangements for the eurozone, passing through parliament without changes in the terms of British membership.