Britain's security services may need to be given greater powers of surveillance to monitor extremists from Isis when they return home to Britain from Iraq and Syria, the former defence secretary Liam Fox has said.

A majority of people will accept that an "ideological battle" means that the authorities will need greater powers to intercept the communications of extremists, Fox said.

The former defence secretary, who was speaking on the Andrew Marr Show on BBC1, said Britain should offer to put its airbases at the disposal of the US to avoid a "horrendous" situation in Iraq as Isis forces pose a threat to Baghdad.

Fox said: "There are those who say if we don't get involved, if we hunker down then we will be fine. There will be no backlash. That is utterly, utterly wrong because the jihadists don't hate us because of what we do. They hate us because of who we are. We can't change that. It is our values and our history that they detest more than anything else."

Fox said the authorities could deprive British citizens returning from Syria and Iraq of their passports. But he said the greatest effort should go towards increasing the power of the state to monitor the communications of extremists. He said: "We have the security services to ensure that they [extremists] are watched and that they don't pose a greater threat."

Asked whether the powers of the security services were insufficient, the former defence secretary said: "That is a real question that we are going to have to ask – whether the security services have adequate resources for an increased threat.

"That is a question politicians will have to take into account in judgments on spending allocations, but also do the powers they have reflect the increasing [threat]? You've got people in the light of Snowden saying that the state has too many powers and we have to restrict the powers of the state."

Asked which powers the state should be given, Fox said: "The whole area of intercept needs to be looked at. We have got a real debate, and it is a genuine debate in a democracy, between the libertarians who say the state must not get too powerful and pretty much the rest of us who say the state must protect itself."

Asked whether this meant more surveillance and increasing the manpower of the security services, he said: "If required it is the first duty of the state to protect its citizens … it is a real worry and it is a problem that is going to be with us for a very long time. At heart it is an ideological battle and we have to realise that we have to win the ideological battle as well."

The remarks by Fox suggests that some figures, particularly on the right, will use the success of extremists in Iraq to challenge the claim by Edward Snowden that the state has amassed too many powers of surveillance. Snowden leaked a series of NSA files to the former Guardian journalist Glenn Greenwald last year.