If the hon. Lady will allow me, I will make some further progress, but I will allow her to intervene on me later.
In order to build the credibility and trust of those under investigations, there are occasions where, in carefully managed circumstances and subject to robust independent safeguards, CHIS may need to participate in criminality themselves. This is an inescapable and essential feature of CHIS use and has always been fundamental to this work. Although I am unable to go into the detail about the specific criminality that a CHIS may participate in, for reasons I will come to, limited examples have been discussed in the public domain. For example, a CHIS may be required to join the organisation that they are seeking to disrupt. This membership alone will sometimes be criminal but will be deemed necessary and proportionate to prevent more serious criminality from taking place. Again, without going into the specifics, the use of that tactic enabled the police and MI5 to disrupt a planned terrorist attack on No. 10 and the then Prime Minister in 2017. The necessity of CHIS participation in criminal conduct has been accepted in the UK and around the world for many years. In December 2019, the Investigatory Powers Tribunal found that MI5 has a lawful basis for this activity and recognised that CHIS participation formed an essential part of MI5’s core activities. I want to reassure the House that this Bill does not confer the power to carry out a new activity, but enables CHIS to continue to deploy the methods that they already use. Notwithstanding those powers, this Bill puts that existing practice onto a clearer statutory footing, putting the matter beyond doubt as to Parliament’s intentions. The Bill provides certainty for CHIS and their handlers and will augment our ability to recruit and retain in the future in this regard. It is important to stress that the Bill does not change the position of CHIS who have previously been properly authorised to participate in criminal activity. It has no retrospective effect.