UK senior government sources say that plans are already in place for a further round of sanctions if Moscow continues with what they term as "brutal and aggressive actions".
Security officials hold that the attempted murder of former Russian spy Sergei Skripal and his daughter Yulia was ordered at the "highest levels" of the Kremlin.
The British Prime Minister Theresa May’s approach, the officials maintained, was "calibrated, calm and firm" and designed to highlight to the international community the gravity of what had occurred and the need for a "robust response".
"Although we have announced this response, further options remain on the table. Economic, diplomatic, legislative and security capabilities can all be brought to bear if needed," a senior Government official said.
"If we don’t feel that what we have done thus far is having the required effect in the short, medium and long term – a change of behaviour from the Kremlin – we will look at them again and revise them," the Independent cited the official as saying.
