European stock markets slipped Monday as investors returned to their desks to digest the latest terror attack in the U.K., banks weighed again and markets reacted to a series of poorer-than-expected economic bulletins.

The Saturday terror attack in London and a renewed general election campaign left U.K.-based investors with a lot to think about, while poorer-than-expected services sector data also added to the uninspiring mood.

Over in continental Europe, services data for May was also poorer than expected for both France and Germany, a source of consternation ahead of Thursday's scheduled ECB rate decision and press conference.

Oil prices were also volatile during the session, with brent crude rising more than 1% only to shed 1.5% before the London close, as traders responded to news that Saudi Arabia and its Arab partners have abandoned Qatar due to its alleged links to terrorism, providing scope for yet more tension in the middle east.  

The FTSE 100 slid 0.29% in London to close at 7,525 for the session while, over in Paris, the CAC 40 index dropped 0.66% to 5,307. 

In southern Europe, the IBEX fell by nearly a quarter percent in Madrid while the FTSE MIB shed close to 1% in Milan. 

easyJet (EJTTF) stock fell close to 3% in response to volatility in oil prices, which came after it emerged that one of the company's largest shareholders has cut its stake below 5%. 

Antofagasta (ANFGY) stock slipped nearly 3% as investors reacted to a fall in copper prices, which also pushed BHP stock lower for the session, although not by quite as much.

Astrazeneca (AZN - Get Report) stock also fell despite it having announced another victory in the oncology department, with its drug Lynparza having proven more effective than chemotherapy in treating a certain type of breast cancer. The stock was down 0.40% at the close. 

Over in continental Europe, a German public holiday meant that Frankfurt was quiet. However, price action in Spanish stocks more than made up for it. 

Banco Popular  (BPESF) stock fell by more than 18% during the Monday session as Spanish lenders came under renewed pressure amid investors concern over capital levels in the country's banking sector.

Popular has been besieged by capital concerns in recent weeks after reports from Reuters suggested that the Single Resolution Board has warned European officials that the bank might need to be wound down in the event that it cannot find a buyer for itself.

Total losses for the stock now sit at close to 50% while, for the year to date, the lender has shed more than 60% of its value. 

It is now pursuing a sale of itself; press reports have labelled Banco Santander (SAN) as a possible buyer, and given the beginning of June expiry of a bailout-related prohibition on corporate transactions, Bankia (BNKXF) could also be in the running.

In France, Societe Generale (SCGLY) saw its stock fall by just less than 0.50% despite it having launched the IPO of its car leasing unit, ALD, that could be valued at up to €6 billion ($6.66 billion).