Islamic State militants and supporters are believed to be using encrypted messaging apps, making it difficult for security services to intercept communications.
A Channel 4 News investigation claimed that at least 115 IS-linked people appear to have used the popular app Surespot in the past six months.
The programme, which looked at users discussing Surespot on Twitter, said the number of IS-linked accounts that mention it seems to have accelerated and believed the attraction may be its functions, similar to WhatsApp or Facebook Messenger but with very high levels of security.
The news comes after police and security agencies expressed concerns that they are losing the ability to intercept telecommunications data as this is a critical tool in interrupting domestic terror plots and monitoring suspects abroad.
Channel 4 News said it found IS-linked accounts which admit online to using the apps when attempting to fundraise for terrorism, discussing the best methods to join IS and to pose questions.
One user wrote: “If anyone wishes to sponsor the mujahideen... Contact me on my Surespot for safeways”.
Meanwhile another user said: “If you want 2 ask questions about Islam, Hijrah [emigration], Jihad or Shaam [Syria]; Ask me on Surespot”.
Others with less expertise seek advice via the app: “Interested in Hijrah [emigration] to Islamic Lands don't know anyone need help. I was told to use Surespot.”
The government is expected to soon introduce new legislation that will revive the so-called “Snooper’s Charter” bill, known as the Draft Communications Data Bill.
The bill, which would increase the data collected about people’s online activity, was shelved in 2013 after the Liberal Democrats opposed it. It is now thought that Home Secretary Theresa May will return the proposals to the agenda after the recent Tory election victory.
The Prime Minister said in January that there should be no method of communication that the government shouldn’t be able to request access to.
However, it would be a difficult thing to achieve as the servers that run the apps hold the information only in heavily-encrypted format that the app companies themselves don’t have any access to.
Although they provide more secure communications than text messages, WhatsApp and Facebook chat, the server owners can’t give information to the police.
Gavin Millard, technical director and information security expert at Tenable Security, told Channel 4 News: “I think the genie is already out of the bottle. So, no matter what steps [the government] take, the people that want to communicate privately will simply pivot and use a different approach.”
“Encryption has been around for a very long time anyway. People just simply adapt it for their need.”
Encrypted messengers apps have become popular in the wake of the Snowden revelations that security and intelligence agencies were gathering data about citizens in bulk, regardless of suspicion.