The lord chancellor Chris Grayling did not have 'perfect' information when he decided to press ahead with two-tier contracts for criminal legal aid - but what information he had was 'sufficient', the government will argue in the High Court on Monday.

The justice secretary's defence against challenges from the Law Society and practitioner groups the Criminal Law Solicitors' Association and London Criminal Courts Solicitors' Association of the legal aid crime duty tender process will be heard on the final day of a three-day judicial review hearing.

According to the lord chancellor's skeleton argument it is widely agreed - including by the CLSA, LCCSA and Society - that the market for criminal legal aid services is inefficient and unsustainable in its current form, with 'too many providers chasing too little work'. In addition, the Ministry of Justice's budget has been cut by about a third in real terms between 2010-11 and 2015-16.

As a result, 'there is a need for very significant reductions in spending in all areas, including criminal legal aid'.

'So far as the lord chancellor is concerned, the need to reduce expenditure is not an abstract matter; it is a concrete reality and it cannot be wished away,' the skeleton argument states.

'By November 2014, the lord chancellor had to consider whether he had enough information on which to proceed to make a decision, or whether he should ask for further analysis or initiate further investigations,' the skeleton argument continues. 

'He concluded that the information before him, while not perfect, was sufficient to enable a decision to be made. Although he could have delayed further, he would not be substantially better informed if he did so.'

The argument notes everyone affected had been given the chance to make their views known on the issues on which they could usefully contribute, and these views were taken into account.

It concludes that there is no basis for impugning the lord chancellor's assessment other than on grounds of rationality, and the decision 'was on any view rational'.

On Friday Lord Justice Laws and Mr Justice Cranston heard Dinah Rose QC, of Blackstone Chambers, set out the Society's challenge.

Chancery Lane argued that the lord chancellor's decision to start the tender process was unlawful because it was 'irrational', 'disproportionate' and based on a 'manifest error'. Such a radical, risky exercise as the legal aid reforms required reasonable investigation, she contended. 

The hearing continues, and is expected to conclude, tomorrow.