European benchmarks turned lower in noon trading Monday after terror struck the Continent once again, this time on the metro system in Russia's St Petersburg.

The latest attack not only soured an optimistic atmosphere among investors; it also risks bringing the threat of terror and its associated discussions back into the foreground as markets await the first round of the French election, which gets underway in late April.

Monday's attack came against a backdrop of brighter economic data and ECB member Benoit Coeure having struck an optimistic tone on the subject of the eurozone economy.

The FTSE 100 fell by 0.55% in London to close at 7,282 while the mid-market FTSE 250 slipped 0.09% to settle at 18,954.

In continental Europe, the DAX fell by 0.50% to close at 12,257 while the CAC 40 in Paris led declines with a steep 0.71% loss, closing at 5,085.

In individual stocks, retailer Next (NXGPY) , media company ITV (ITVPY) and Hikma Pharmaceuticals (HKMPY) were among the biggest fallers on the large cap FTSE 100 index, although those with the bloodiest noses at the close were shareholders in chip designer Imagination Technologies (IGNMF)  , whose shares fell by more than 60%.

Imagination told investors that its largest customer, Apple (AAP) - Get Report has deserted it.

Graphics card royalties paid by the U.S. tech titan account for the lion's share of revenue at Imagination.

However, Apple has been developing its own graphics capability and has said it plans to stop using Imagination in about 18 months. Ironically, Imagination sent Apple packing in January 2016, when the i-Phone maker attempted to talk to the company about the prospect of a takeover.

In continental Europe, Credit Suisse (CS) - Get Report continued to fall, down more than 2%, in response to a Friday's news that it is being investigated in relation to a tax fraud and money laundering probe.

The European banking sector was weak, proving a weight around the ankles of markets from very early on.

The biggest fallers included Deutsche Bank (DB) - Get Report , Commerzbank (CRZBY) , Lloyds (LYG) - Get Report, Barclays (BCS) - Get Report , Santander (SAN) - Get Report .

Analysts at Berenberg have recently advocated selling and then getting short on the stocks of all of the above, along with another ten European banks.

In Paris, Societe Generale (SCGLY) and BNP Paribas (BNPQY) were the top fallers, with losses of between 2% and 3% each. Both were also named as targets for short positions by analysts at Berenberg.