Neil Basu

It would create an immediate risk that people could come to this country who were serious offenders, either wanted or still serial and serious offenders committing crimes in this country, and we would not know about it, it creates that risk.

We can make them [ the damaging effects ] less, but they would be slower systems, those systems and tools were developed in the EU for very good reason. They were very good. In a no deal we'd lose all that. We'd have to renegotiate it.

This latest horrendous turn of events has only served to strengthen the resolve of our investigation team as we work to identify those responsible for this outrageous, reckless and barbaric act, they are unable to say at this moment whether or not the nerve agent found in this incident is linked to the attack on Sergei and Yulia Skripal.

Dawn leaves behind her family, including three children, and our thoughts and prayers are with them at this extremely difficult time.

I don't have any intelligence or evidence that they were targeted in any way. There is nothing in their background to suggest that at all, we are not in a position to say whether the nerve agent was from the same batch that the Skripals were exposed to. The possibility that these two investigations might be linked is clearly a line of inquiry for us.

This will look similar to some of the activity that took place in Salisbury earlier this year, again, this is a precautionary, but necessary measure that allows officers to safely carry out meticulous and systematic searches for evidence to support the investigation. This must be done with great care, as you will appreciate, to ensure there is no outstanding risk to both those brave officers and the public.

Following the detailed analysis of these samples, we can confirm that the man and woman have been exposed to the nerve agent Novichok, which has been identified as the same nerve agent that contaminated both Yulia and Sergei Skripal.

We are not in a position to say whether the nerve agent was from the same batch that the Skripals were exposed to, the possibility that these two investigations might be linked is clearly a line of enquiry for us.