Police riot vans at a Bed and Breakfast near Hillingdon tube station raised eyebrows after a number of officers were seen on site.
Uniformed police were on site carrying out a search after presenting the warrant for drugs at the property.
A passer-by, Jeff Rooke, tweeted a picture of the sight at Hillingdon Lodge B&B, on Hercies Road, at 9am on Thursday, February 18.
He said: "There's two riot vans raiding Hillingdon Lodge at the moment.
"There's obviously something of interest there."
An employer at the B&B, which has a 1.5 star rating on Trip Advisor, confirmed that they are open and still operating as a bed and breakfast.
A Metropolitan Police spokesperson said: "Police in Hillingdon executed a drugs warrant at an address in Hercies Road, Hillingdon, today, Thursday, 18 February at approximately 9am.
"No arrests have been made.
It is unknown as yet if police recovered drugs at the scene.