Officers seized the Maserati GranCabrio - a basic model of which can cost up to £100,000 new - on King's Road in Kingston on suspicion of it having no insurance.
The Met said the car was impounded and the owner would be summoned to court.
If found guilty the owner, who has not been named, faces a minimum £300 fine and six points on their licence
A Kingston Police spokesman said the driver was pulled over because officers thought the car seemed very expensive for a learner to be driving.
In March, a "gold fleet" including a Lamborghini Aventador, a Mercedes G63 6x6 and a Bentley Flying Spur were all spotted in Knightsbridge with parking tickets on their windscreens.

Simon, 29, joined the Wildcats from Catalans Dragons, and has played nine times in Super League this year.
Coach Chris Chester told BBC Radio Leeds: "It's massive and I'm really pleased that he has put pen to paper.
"He has been a stand-out player for us over the last few weeks and it's a real statement of intent from the club."

The 20-year-old has made seven senior appearances for Rovers so far in his career.
Born in Wales, he has previously had loan spells at non-league sides Taunton Town and Bath City.
One of five players offered a new deal by boss Darrell Clarke at the end of the season, Broom is the second to sign on so far, after defender James Clarke.

The game features cards with a series of quiz questions, but some of the answers given are incorrect.
One answer claims the moon is 225 miles away from the earth - instead of about 238,900 miles.
Manufacturers Paul Lamond Games said they "unreservedly apologise" and added replacement cards would be issued.
It is understood at least six of the 50 answers in one round of the game - which costs Â£19.99 - are incorrect.
One answer placed Stonehenge in Somerset instead of Wiltshire and a maths question suggested two cubed was bigger than three squared.
It also said Albert Einstein died in 1949 instead of 1955 and gave the number of Coronation Street episodes to date as 8,000, when the actual figure is more than 9,000.
One customer who bought the game told The Sun: "I couldn't believe it, the answers are so ridiculous... [but] the kids won't accept the game could possibly be wrong."
A representative for Paul Lamond Games told the BBC: "We have been made aware of some mistakes with the answers to the questions within the first production run of this game."
"These have now been corrected and we would like to unreservedly apologise for these errors.
"Any affected customer can email us stating their name and full address and we will send out a replacement set of corrected cards free of charge."
The company's email address is available on their official website.
Ant & Dec - whose full names are Anthony McPartlin and Declan Donnelly - have hosted Saturday Night Takeaway on ITV since 2002, although the show took a four-year break from 2009.
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A gold supercar with L-plates was seized by police in west London, leaving its driver by the roadside.
[NEXT_CONCEPT]
Wakefield Trinity Wildcats prop Mickael Simon has signed a one-year contract extension, keeping him at the club until the end of the 2017 season.
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Bristol Rovers midfielder Ryan Broom has signed an extended contract with the League One club.
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The makers of Ant & Dec's Saturday Night Takeaway board game have apologised after it was found to have several errors.