A £5m "ring of steel" surrounding London's Square Mile could be installed to protect the City from terrorist attacks.
Measures including manned checkpoints, rising steel bollards and crash-proof barricades has been proposed by the City of London Corporation on the advice of Mi5 and counter-terrorism police.
The proposed security ring will surround Liverpool Street, the Bank of England and Fenchurch Street, an area that includes the Gherkin, the Lloyd's Building and Heron Tower.
Skyscrapers in the area are regarded as at risk to vehicle-based terror and the new security proposals follow the attack on a Berlin Christmas market by Tunisian radical Anis Amri who drove a lorry into crowds, leaving 12 people dead and a further 49 injured.
Anti-terror forces are reviewing the vulnerability of all skyscrapers and landmarks in the capital following the attack.
"The local situation has changed significantly over the past two years with several large-scale redevelopments approved or planned," said the City of London Corporation's director of built environment Simon Glyn
"The scale of these developments requires much greater levels of security than can be delivered on a site-by-site basis and an area-wide solution is recommended.
“Investment in the security of the Eastern City Cluster, which is one of the City’s most crowded places and a significant target for terrorist attack, is considered both essential infrastructure and an important offer by the City of London to current and future occupiers in the area that may determine the future investment decisions of these stakeholders."
The City originally had a "ring of steel" in the 1990s following IRA bombs at the Baltic Exchange and in Bishopsgate in the 1980s.
After the IRA declared a ceasefire in 1994, the measures have largely been phased out.