The London Underground (LU) remains "wide open" to further terrorist attacks, the Tory Party has claimed.
Mr Mercer accused the government of complacency
Homeland Security spokesman Patrick Mercer MP said the government has been complacent about safety.
He added "virtually nothing" had been done to make the Tube less vulnerable after the 7 July 2005 bombings, which killed 52 people.
But an LU spokesman said there were 50% more police on the Tube and thousands more CCTV cameras since 7 July.
Mr Mercer said there was no information for passengers on the network about what to do in an emergency.
"The Tube is wide open to further attacks and very little has been done to make it any safer," said Mr Mercer.
"The government is hugely complacent about Tube safety and security."
The MP said the network was the target of an attempted attack on 21 July 2005 and "we have almost certainly had foiled attacks as well".
But an LU spokesman said: "Patrick Mercer is wrong to suggest that the Tube is no safer than it was prior to 7 July.
"There are now thousands more CCTV cameras than there were on 7 July.
"The number of British Transport Police officers on the Tube network has increased by 50% under Transport for London.
"We have posters giving safety information at all stations and this is supported by regular announcements by Tube staff.
"New emergency information signs are currently on Waterloo & City and refurbished District Line trains and will be on all trains by the end of next month."