"The UK has an advanced system of special advocates who represent the interests of clients but also have access to certain classified information which may not be able to be presented in other circumstances," he told Parliament. "This system importantly balances security needs with ensuring fair representation during judicial proceedings. "Speaking with UK agencies, the independent reviewer of terrorism legislation and a special advocate provided an invaluable insight into the benefits of this approach." As chairman of the parliamentary joint committee on intelligence and security, Mr Tehan has an influential voice within the Coalition on security issues. Fairfax Media asked Mr Tehan whether he advocated Australia's adoption of the same approach as Britain, but he had not responded by deadline on Monday. The Abbott government is preparing further national security legislation that is expected to make some adjustments in response to the experiences of police and security agencies from the wave of terrorism-related arrests over the past year.

This new legislation is expected to include changes that will enable police to use classified intelligence in affidavits to obtain search warrants, which will require security-cleared judges to consider the applications in secret. Agencies have become increasingly concerned that existing laws do not allow them to use such material while still protecting the identities of their informants and their own capabilities. The further step of British-style secret courts with special advocates is not expected to be part of the next wave of legislation. However, the Abbott government has in its recent changes to national security laws repeatedly followed examples set by Britain, including on issues such as citizenship and data retention. Britain has used special advocates since 1997. Canada also uses special advocates in closed courts for certain national security and immigration cases. This system importantly balances security needs with ensuring fair representation during judicial proceedings

However, the approach has been controversial. The special advocates themselves in Britain, in a joint-submission to the government in 2012, said the closed courts "represent a departure from the foundational principle of natural justice that all parties are entitled to see and challenge all the evidence relied upon before the court and to combat that evidence by calling evidence of their own". The Abbott government's next tranche of counter-terrorism laws are also expected to include some changes to the system of control orders, which are issued by a court and can impose curfews on terrorism suspects, compel them to wear a tracking device and restrict who they can communicate with. Follow us on Twitter