Until October 2004, ACAS conciliation officers were under a statutory duty to seek to promote a settlement in nearly all claims made to an employment tribunal up until all matters of liability and remedy had been determined.

The Employment Tribunals Rules of Procedure, contained within schedule 1 to the Employment Tribunals (Constitution and Rules of Procedure) Regulations 2004, introduced provisions that in most cases restricted the ACAS duty to conciliate to a fixed period of seven or thirteen weeks. Although ACAS could exercise its discretion to conciliate after that period was over, it chose to do so only in exceptional circumstances.

ACAS has recently announced a change in policy. ACAS will now exercise its discretion to extend the conciliation period if either party requests it or if an ACAS conciliator considers that there is a reasonable prospect that an extension may assist in resolving the case without the need for determination by the tribunal. In practice, this means that, as long as settlement is still an option, there will effectively be no time limit on conciliation.

This change in policy resulted from the proposed abolition of fixed conciliation periods in the Employment Bill, which is expected to take effect from April 2009, and follows the unequivocal findings of the Gibbons Review. The Gibbons Review found that, since their introduction in October 2004, fixed conciliation periods had not led to more or earlier resolution of disputes about individual employment rights and proposed that these restrictions should be removed.