LONDON (BLOOMBERG) - The sheer audacity of Russia's chemical-weapon attack on Britain can be traced through the journey of a small - and fake - Nina Ricci "Premier Jour" perfume bottle.

It contained Novichok, a lethal Soviet-era nerve agent, and was smuggled from Russia into Britain on a regular Aeroflot flight. Landing at Gatwick Airport - used by more than 45 million travellers a year - it passed through London Victoria and Waterloo train stations and a budget hotel on its way to Salisbury, a sleepy mediaeval town in southern England.

There, in broad daylight on a Sunday afternoon, it was sprayed onto a door handle at the home of a former Russian spy, Mr Sergei Skripal.

Prime Minister Theresa May hinted that Britain would retaliate using "all the tools in our national security apparatus", but it is difficult to imagine what it - or any Western power - can do to prevent this kind of attack. Russia's defiance underscores that dilemma.

"We repeatedly asked Russia to account for what happened in Salisbury in March, and they have replied with obfuscation and lies,'' Mrs May said in Parliament on Wednesday (Sept 5). She added, to awkward chuckles, "they even claimed that I, myself, invented Novichok".

Britain can hurt individual Russians with visa restrictions and by targeting illegitimate personal wealth; it can also push allies for more sanctions but tough geopolitical action will be harder.

For example, on Thursday, Britain will put the issue in front of the United Nations Security Council, a decision-making body where Russia regularly uses its veto when its interests are threatened.

Britain deployed 250 detectives to trawl through 11,000 hours of CCTV images and took more than 1,400 witness statements to piece together what happened. Britain knows the names - or aliases, at least - of the two Russians who carried out the attack, which Mrs May said was "almost certainly" authorised by the Kremlin.

Jeans and Sneakers

CCTV images released by police on Wednesday showed Alexander Petrov and Ruslan Boshirov - one bearded, one clean-shaven and zippered up against the snow - blending in among the tourists and locals in Salisbury, which was bustling with its weekly Saturday market.

Dressed in jeans, sneakers and hats, they stayed for a couple of hours before returning to the capital.

When they retraced their journey the very next day, their two-hour visit ended very differently. They arrived by train in Salisbury at 11.48am on March 4 and left the same way shortly before 2pm. By 5pm, Mr Skripal and his daughter Yulia had collapsed on a park bench near a shopping mall in critical condition.

Britain said the men - who travelled under aliases on fake passports issued by Russia - are agents in the Russian GRU military foreign intelligence service, which traces its roots to Soviet military intelligence and had kept a low profile for decades.

In recent years, though, it has been accused of a broad range of overseas operations, from the 2014 annexation of Crimea to cyber attacks in the United States and Europe. GRU agents are also operating on the ground in Syria, where they help direct Russian airstrikes.

British Security Minister Ben Wallace said Russian President Vladimir Putin must "ultimately" bear responsibility because he is the head of state and there is a direct line of command from the Kremlin, through the military, to the GRU.

"I don't think anyone can ever say Mr Putin isn't in control of his state," Mr Wallace told BBC Radio 4 on Thursday. "The GRU is, without doubt, not rogue; it is led, linked, to both the senior members of the Russian general staff and the defence minister, and through that into the Kremlin and the president's office."

Former colonel

Mr Skripal himself was a colonel in the GRU before he was convicted of spying for Britain and sentenced to 13 years in prison in 2006. He was pardoned and sent to Britain in 2010 as part of a swap for Russian agents captured in the US.

Both he and his daughter survived the attack, and are now in hiding.

The fallout didn't end there. On June 27, local man Charlie Rowley discovered the abandoned perfume bottle in a charity bin in Salisbury, and took it to his home in nearby Amesbury. Three days later, he attached the applicator and gave it to his partner, Ms Dawn Sturgess, who sprayed the nerve agent directly onto her wrists. Both fell ill and were taken to hospital.

Within a week, Ms Sturgess, a 44-year-old mother of three, was dead.

In the immediate aftermath of the attack on the Skripals, Mrs May managed to secure international backing for the expulsion of Russian diplomats around the world. Now her government would like for more action.

'Disinformation'

To avoid giving Russia a head-start on what British officials call its "disinformation campaign", the government started briefing allies on Tuesday evening. Mrs May spoke to US President Donald Trump by phone to update him on the case.

While relations with Russia have been soured, Britain remains a favourite home for Russian tycoons and their families. London, especially, has been a source of financing and expertise for companies.

Further sanctions, especially if Britain won support from allies in the US and Europe, could effectively deepen Russia's economic isolation.

One option would be to raise the issue when Mrs May addresses the UN General Assembly in New York at the end of the month - that's when Mr Trump said he would be seeing Mrs May next after talking to her on Tuesday night. There's another potential opportunity at an EU summit in Salzburg on Sept 19-20.

Fears of further sanctions from the US, fuelled in part by the announcement last month of restrictions related to the Skripal case, have battered the ruble and Russian government bonds in recent weeks. The currency is now near two-year lows against the dollar, while the Finance Ministry on Wednesday had to cancel a bond auction because of weak demand.

Unexplained Wealth

In Britain, legislation also came into force in January allowing the government to use Unexplained Wealth Orders to require asset owners to prove they could afford them through legitimate means. So far, the National Crime Agency has only used the tool once - against the wife of an international banker, who owns two properties worth £22 million (S$39 million).

The government is also reviewing investor visas handed out to about 700 Russians before 2015, when it took steps to tighten the rules.

One action that looks unlikely is a murder trial for Petrov and Boshirov. Despite issuing Europe-wide warrants for their arrest, Britain said it won't apply for their extradition - because Russia's Constitution doesn't allow it.