The drugs were unlicensed, generic versions of Pfizer's Viagra (sildenafil citrate) and Eli Lilly's Cialis (tadalafil), going by the names Kamagra (in tablet and sachet form), Lovegra and Apcalis.
The confiscated goods were worth around £350,000 (€519,000), and most likely manufactured in the Far East before being imported into the UK, according to an MHRA spokesperson.
Viagra and Cialis were two of the most widely faked drugs in Europe over 2006, with a rich black market trade in imitation and purportedly genuine tablets gnawing away at authentic drug sales and posing a significant risk to the health of those who purchase them.
"It is essential the medicines are licensed correctly," said MHRA head of criminal operations Danny Lee-Frost.
"The type of medicines we seized cannot be guaranteed to be acceptably safe because they have not gone through the correct licensing regulatory process.
At best these medicines could be a waste of money, at worst they could be severely detrimental to your health."
Although the MHRA was unable to comment on how the seized meds were likely to reach the market, a spokesperson from the agency did agree that the unlicensed medicines are widely available through a host of online pharmacies claiming to offer cheaper, easily accessible alternatives to the authentic branded drugs.
"There are people out there illegally selling these medicines online," the MHRA spokesperson told in-PharmaTechnologist.com.
"These male impotence drugs, lifestyle drugs, are certainly the kind of things widely peddled online."
Many of these internet pharmacies will be located in countries outside the regions regulated by the MHRA, with a similar situation for equivalent authorities representing other countries.
As such, the agency warns that the risk of substandard or fake medicines is vastly increased through buying online.
In a bid to try and establish some kind of standard or policing method of these internet pharmacies, in 2006 the Royal Pharmaceutical Society of Great Britain (RPSGB) initiated a pilot logo scheme to help the public identify whether a specific website is linked to a bona fide, registered pharmacy.
Through the scheme, online pharmacies carry a logo which, although not an accreditation by the RPSGB in any way, legitimises the pharmacy's online activity and links it to a real bricks-and-mortar pharmacy on the street.
The initial pilot involved 20 online pharmacies, and once the scheme is launched fully, it will be compulsory for all pharmacies registered with the RPSGB and trading online to carry the logo.
The project is still in development, and although original plans were for the scheme to launch next month, technical delays have meant that it is more likely that the fully-fledged logo programme will kick off in the new year.
Last week's West London seizure was the latest success in the MHRA Enforcement Team's continuous clamp-down on the sale and distribution of unlicensed and illegal drug products.
Although no arrests have been made as yet, any individual convicted of offences under the UK Medicines Act can be sentenced to a maximum of two years imprisonment and/or an unlimited fine.
If found to have financially benefited from the proceeds of the crime, the MHRA can also cite the Proceeds of Crime Act in order to recoup illicit earnings from guilty parties.