Parties of all political creeds have been accused of neglecting all aspects of law and order, so there is little point in making a political football out of the issue.
The issue here is convicted terrorrists;
Do you let a rabid dog run free?
Do you let a Wuhan coronavirus carrier run free?
Why let an unreformed terrorist free?

The antiterrorist forces are limited, full surveillance of just one person requires many people.

There s also a human rights aspect. The surveillance tools for antiterrorism can also be applied elswhere. Who polices the "policemen" The UK is the most surveilled country in the world and few are aware of just how deep it can go.
For example: In Ireland(where the following information is in the public domain)
Under the 2009 Act:
    Gardaí or the Defence Forces can tap phones and listen to phone calls, open and read letters before they arrive to their recipient, and (potentially) read emails
    Gardaí, the Defence Forces and Revenue can secretly record you with audio and video devices
    For three months
    They can break into your home to implant a device, and again to remove it
    If they can, they have to get permission from a District Court judge, but if it’s an emergency, a “Superior Officer” in each agency decides, and they get 72 hours to engage in the surveillance
    Gardaí, the Defence Forces and Revenue can secretly put a tracking device on your vehicle, and follow your movements
    For four months
    Without permission from a District Court judge, but with the approval of a “Superior Officer” within each agency.

With surveillance we are expected to take a lot on trust. In the uk surveillance extends much further and much deeper. Back in the days of ban the bomb marches the security forces kept tabs on participants and likewise union activists (to name but a few). During the subsequent 50 years their capabilities haave expanded much further.
Whatever route is chosen to deal with terrorists long term will involve a moral and financial discussion. Also the more resources developed to identify,monitor and isolate terrorists, the more they can be used against the people. With an opposition party barely even existing in name, all society is at potential risk from the state.