At least 20,000 mobile phones and sim cards were discovered in prisons last year - more than double the number recorded two years earlier.
The proliferation of handsets in jails has been linked to drugs and organised crime, while some inmates have used the devices to film themselves and post videos on websites such as Facebook.
Justice Secretary Liz Truss has announced new measures to crack down on their use, including giving prisons power to jam the signals.
But David Hanson, the Labour former justice minister who uncovered the latest figures in a parliamentary question, urged tougher action.
This is a shocking failure by the Government
David Hanson, the Labour former justice minister
At least 20,075 mobile phones and sim cards were found in prisons in 2016, according to the Ministry of Justice numbers.
This is up around a fifth (18%) on the 16,987 finds - which can include handsets, sim, USB or media cards - which were found the year before, and more than double the 9,745 mobiles and sims found in 2014, according to the figures.
The Ministry of Justice cautioned against drawing direct comparisons with the numbers as a new and "enhanced" incident reporting regime was introduced in October 2015 which "allowed better recording of the number of mobile phones and sim cards found".
But Mr Hanson said the figures show that an "astounding number of mobile phones are now washing through our prison system".
He said: "Each one of these phones and sim cards enables criminals to gain access to the outside world, empowering them to undertake further criminal activity such as intimidation of juries, operating drugs smuggling into their prison, or ordering violent attacks on people.
"There is clearly an epidemic of banned phones entering our prisons.
"These figures demonstrate how many phones are found, but don't tell us how long it took to find them. Therefore, these mobiles and sims could have been in the hands of convicted criminals for weeks, if not months. This is a shocking failure by the Government."
Answering the parliamentary question, Prisons Minister Sam Gyimah said the Government has brought in tough measures to find and confiscate phones.
He said: "The illicit use of mobile phones undermines the safety and security of prisons, which is why we are taking urgent and decisive action.
"Under measures introduced in late 2016, we can now apply for Telecommunications Restriction Orders at court to block specific mobile phones being used in prisons.
"Since the legislation was introduced in August, we have had more than 150 mobile phones cut off.
"In addition, we have announced new measures in the Prison and Courts Bill that will allow the Secretary of State to authorise mobile network operators to block illicit mobile phone signals across entire prison sites.
"This will allow industry experts to work more creatively and effectively to block signals and means that we won't require a court order to stop the illicit and harmful use of mobile phones in prisons."