City banks are being warned by police of a "real and ever-present" threat from the Real IRA.
The force is urging City workers to stay vigilant and report anything suspicious.
Although the official terrorism threat level has not been raised, the warnings have come after leaders of the dissident republican group told the Guardian of their plans to attack "high-profile economic targets".
They say: "The role of bankers and the institutions they serve in financing Britain's colonial and capitalist system has not gone unnoticed."
Santander considering flotation
Santander could be on the verge of launching a stock market flotation on the London market.
The institution's UK arm, which was formed from Abbey, Alliance & Leicester and Bradford & Bingley, may launch a £20bn IPO by the end of this year, the Telegraph reports.
With the company continuing an aggressive campaign of acquisitions in the UK and abroad, observers are speculating Santander may look to raise money to boost its capital ratios.
The firm recently completed the purchase of 318 Royal Bank of Scotland branches, giving it the fourth-largest branch network in the UK.
RBS board member argues against remuneration disclosure
An RBS board member has claimed the demand for public disclosure about bankers' remuneration may actually be driving up bonuses.
Speaking at the ABI conference, Penny Hughes, chair of the bank's remuneration committee, said "disclosure has been part of the acceleration of pay" as employees look to gain parity with their peers, according to the Guardian.
Meanwhile, Peter Middleton, former chairman of Salomon Brothers, agreed with Hughes' assessment and urged boards to stand up against the demand for transparency on pay from institutional shareholders.
Putting the tech into protection
Square Mile’s series of informal interviews
Fallout from Haywood suspension
Launching later in 2019
£80bn funds under calculation