The European Union’s Second Generation Schengen Information System (SIS II) was accessed by the UK over 500 million times last year.

Now the cross-party Home Affairs committee has warned it is “seriously concerned” that the UK losing access to the system after Brexit.

SIS II is the largest information system for public security in Europe, used by 29 nations for national security, border control and law enforcement.

As well as intelligence on persons of interest, it also holds information on stolen banknotes, cars, vans, firearms and identity documents.

SIS IIEU Intransigent on UK Participation in SIS II

In an analysis of Home Office preparations for the UK exiting the EU, published this morning [pdf], MPs raised a litany of security cooperation concerns.

“We are deeply disappointed at the EU’s resistance to UK participation in the SIS II database given the importance of this security cooperation to both the UK and the EU” they wrote, adding: “There has also been a concerning lack of progress in securing the UK’s future relationship with Europol and the European Arrest Warrant. As it stands there is a significant risk that the UK and the EU are facing a security downgrade.”

The committee, chaired by Labour’s Yvette Cooper MP, said it is “seriously damaging” that the Government is not being open with Parliament on the implications of the deal it has reached with the EU.

“We disagree with the Home Secretary’s description of access to SIS II as merely a “nice to have”, and we are seriously worried about complacency in this area. We urge the Government to be clearer with Parliament about the security risks.”

IT databases to support an independent UK immigration policy are also a concern, the committee emphasised, saying the Home Office has persistently struggled to upgrade its IT systems.

“In 2010, the Home Office attempted to replace its immigration casework system (CID) and 20 other IT and paper-based systems with a new Immigration Case Work (ICW) computer. This programme was closed in 2013, after £347 million in spending, despite having failed to deliver all the planned functions.”

“Attempts to deliver other IT systems, such as the e-borders programme to collect advance passenger information, or the Department’s programme to upgrade the communications systems used by UK emergency services, have also experienced significant problems.”

See also: “Substantial Risk” of Brexit IT Disruption to Agriculture, Chemicals