Soaring numbers of migrants are using fraudulent documents as they attempt to reach Britain, a report from the EU's border agency has revealed.
The number of people aiming to get to the UK with false papers jumped by 70% last year, the Frontex study indicates.
The disclosure came in a risk analysis which also warned terrorists are exploiting the migrant crisis to travel unchecked through the continent.
It said: "The number of persons aiming to get to the UK with fraudulent documents significantly increased (+70%) compared to 2014.
"This trend is mostly attributable to the increasing number of Albanian nationals often misusing Italian and Greek ID cards followed by Ukrainian nationals abusing authentic Polish ID cards.
"Other nationalities aiming to reach the UK with fraudulent documents were Syrian, Iranian and Chinese nationals."
Overall there had been a "marked increase" in the number of document fraud incidents recorded on movements within the EU's Schengen area.
The report said: "For the second year in a row, there were more fraudulent documents detected on intra-EU/Schengen movements than during border checks on passengers arriving from third countries.
"This is partly due to the large number of migrants undertaking secondary movements within the EU, often with fraudulent documents obtained in the country of entry to the EU."
Britain is not part of the Schengen zone, which allows passport-free movement around the bloc.
Keith Vaz, chairman of the Commons Home Affairs Committee, said: "The extent of the fraud revealed in this report poses real dangers for our security and undermines our immigration system.
"When a British immigration officer is presented with an Italian or Greek ID they are clearly unaware of the history or misuse of that document."
He called for specialist equipment which can immediately check identity documents to be rolled out across the EU.
The Labour MP added: "Countries which are a source of these fraudulent documents, especially those who aspire to EU membership, must tackle this growing problem, and co-operate closely with Europol and other border agencies across the EU. This is simply not happening at present."
Security risks associated with the abuse of Syrian passports were also highlighted.
Criminal organisations have access to a large number of stolen blank Syrian passports and printers used for their personalisation, the report said.
It added: "This allows them to produce genuine-looking passports, which may be difficult to identify even by experienced document experts."
Concerns have repeatedly been raised that Islamic State has the ability to create fake Syrian passports.
Two of the terrorists involved in the Paris attacks in November had previously presented fraudulent Syrian documents to speed up their registration process, the report said.
The agency said there is no EU-wide system of document inspection performance, while increasingly sophisticated physical and security features of travel documents present "significant challenges for border-control officers".
An exercise showed that the performance of technical equipment shows "a degree of variability, indecision and inconsistency", resulting in a number of false documents being incorrectly accepted as genuine.
Concerns were also raised about compliance with a requirement to take and log the fingerprints of third-party nationals.
Under EU regulations countries are supposed to transmit fingerprints to a central system within 72 hours.
The measure is a crucial plank of the so-called Dublin regulations, which state that asylum applications should be considered in the first country a claimant reaches.
However, the Frontex analysis, published on Tuesday, said: "The reality is that fingerprinting of all persons detected crossing illegally the border is not possible or of poor quality, and in any case, is often not transmitted promptly to the Eurodac central database."
Justice minister and Vote Leave supporter Dominic Raab said: " This important report by the EU accepts that fraudulent applications into the EU are rife and systematically being missed.
"With the number of people trying to enter the UK fraudulently from Europe surging by 70% in the last year alone, EU law ties our hands by forcing us to rely on travel documents issued by other EU countries, and prevents us from issuing our own."
A spokesman for Britain Stronger in Europe said: "Britain has full control over our borders because we are not part of the EU's Schengen area.
"Britain's deal with the EU gives us the best of both worlds - opting in to things that help keep us safe, like co-operation on security issues, but opting out of things that do not work for us, like the borderless Schengen area."
The Home Office said the passports of all passengers entering the UK are inspected by Border Force officers to ensure the owners of fraudulent documents are prevented from entering the country.