Scientists who use animals in research will have to provide extra information to funding bodies to demonstrate that they are not using more than the minimum necessary.
They will also be required to ensure that the welfare standards of any overseas research partners comply with the principles of UK legislation.
These changes are contained in new guidelines for using animals in research published this week by five of the UK's major research funders.
Researchers seeking new grants for work involving animals will be obliged to adhere to the guidelines, "Responsibility in the use of animals in bioscience research: expectations of the major research council and charitable funding bodies".
The guidelines outline the legal controls on using animals in research and detail how researchers should apply the 3Rs - replacement, refinement and reduction. The protocols, co-ordinated by the National Centre for the Replacement, Refinement and Reduction of Animals in research (NC3Rs), are intended to help researchers who use animals in universities and research council institutes - and their laboratory staff.
"There are various obligations on researchers to implement the 3Rs, but they don't always manage to implement them fully," said Mark Prescott, the programme manager at the NC3Rs. "This document will assist them in doing that."
Although some funders have published guidance before, this is the first time the major research funders have come together to produce a common set of principles for research on "vertebrates", Dr Prescott said.
"The guidelines have teeth because they are linked to funding ... If you put an application in, and the referees and the review panel of the funding body are not confident that you are applying the guidelines - and you can't address their concerns - they won't support the work."
The document also applies to researchers who study animals in their natural habitats.
Participating alongside the NC3Rs are the Medical Research Council, the Biotechnology and Biological Sciences Research Council, the Natural Environment Research Council and the Wellcome Trust charity. It is hoped other charities will follow suit.
Under the Animals (Scientific Procedures) Act 1986, which regulates animal research in the UK, there is a legal obligation to implement the 3Rs, which state that a project should use the minimum number of animals required to answer the scientific question being investigated. However, Dr Prescott said, the Act contains few specific details about how researchers must meet the obligations, and not all funders have spelt out their expectations for researchers.
"A lot of people just think about their study design and their sample size for minimising numbers ... But in this guidance we are saying you need to think about your entire programme of work," Dr Prescott said.
"If you are breeding animals, how many are you breeding? Can you schedule experiments? And how have you established what is the minimum number to use in each experiment?
"In the past, a researcher might have said, 'I propose to use X dogs to answer this question, and this is the minimum I need.' Now researchers will be required to provide evidence of how they arrived at those sample sizes."
The Wellcome Trust has already updated its grant application forms to reflect the changes, Dr Prescott said, and research councils will follow suit.
Also introduced are new rules to deal with laboratory standards outside the UK. Although some funders have previously had statements on overseas collaborations, it was often unclear who had responsibility for ensuring consistent welfare and ethical standards, Dr Prescott explained.
"What research funders are now saying (through the guidance) is that researchers and their local ethics committee need to investigate the welfare standards at the overseas laboratories and make a judgment about whether those standards are consistent with what you would expect in the UK ... any significant deviations need prior approval from the funding body," he said.
The guidelines also introduce a new commitment from funders to "consider requests in grant proposals for resources for implementing the 3Rs" and to "recognise the publishing of significant and original contributions to the development of the 3Rs", Dr Prescott said. Recognition will come through reviews of research council institutes and in progress and final reports.
Clare Stanford, a reader in psychopharmacology at University College London, welcomed the guidelines. "I think a lot of scientists may be apprehensive because they might think this is another bureaucratic obstacle, but it is absolutely not the case. It is a very useful document that describes the stringently regulated situation as it stands.
"No scientists with any integrity would want to collaborate with a laboratory whose ethical and welfare standards fall below those of the UK," she added.
Further information: http://www.nc3rs.org.uk/