LONDON (Reuters) -Tesla's sales rout in some European markets extended to an eighth month in August amid mounting competition from both Chinese EV rivals and traditional automakers, as well as a backlash against CEO Elon Musk's courting of far-right parties.

Car registration numbers from France, Denmark and Sweden - the first European countries to report monthly numbers for August - also showed that Tesla's revamped Model Y has had little impact on stemming declining sales.

Data from France on Monday showed that registrations of new Tesla cars fell 47.3% in August versus the same month in 2024, while the overall car market grew nearly 2.2%.

Tesla registrations fell more than 84% in Sweden - where electric vehicle sales were flat and the market overall was up 6% - and dropped 42% in Denmark.

Norway, where Tesla has deep roots and virtually all new car sales are electric, remained an outlier with a 21.3% jump in registrations for the U.S. EV maker. But Chinese rival BYD saw registrations spike 218%.

Tesla's biggest European markets are Germany and the UK, which have also seen sales slump this year but have yet to report August sales.

Tesla has several problems in Europe.

The company has a small ageing lineup and has not released a new mass-market model since the Model Y in 2020, while new Chinese rivals and traditional automakers alike are flooding the market with fresh models.

"One reason we are continuing to see disappointing Tesla volumes can partially be attributed to a more competitive market environment," said Matthias Schmidt, European autos market analyst at Schmidt Automotive.

Schmidt added that Musk's insistence during the automaker's second-quarter investor call in July that "there are no issues with Tesla volumes on the European market", when its market share in western Europe fell to 1.7% in the first half of the year from 2.5% in 2024, made him "sound delusional."

Earlier this year Tesla representatives in Europe had argued that the automaker's sales decline was largely because production was shifting over to the revamped Model Y, which was Europe's top-selling car in 2023.

Deliveries of the revised Model Y began across much of Europe in June, but Model Y sales were down 46.5% in Denmark in August and 87% in Sweden.

Tesla's competitive problems have been compounded by Musk's politics - he helped bankroll Donald Trump's U.S. presidential election win last year and has championed European far-right parties - which have sparked a fierce consumer backlash.

Ginny Buckley, CEO of Electrifying.com, said the EV advice website has been tracking consumer sentiment towards Tesla since the beginning of the year.

"What's clear is that Musk's influence on the brand has become increasingly polarizing," Buckley said.

Over half of those surveyed by Electrifying.com said Elon Musk is putting them off buying a Tesla, "signalling Tesla's dominance is no longer a given."

Andy Leyland, co-founder of supply chain specialist SC Insights, said aside from increased competition and "stagnant product lines", Tesla faces "decreased brand loyalty and a loss of technological advantage."

He added that Tesla's sales are also being undermined by the low cost of used Tesla EVs in the secondhand market.

Tesla slashed the price of new cars dramatically starting in 2023, seriously undermining the value of used Teslas that are now being snapped up.

Marketcheck, which collects used vehicle data in the United Kingdom, said that sales of used Teslas hit a record in July, jumping 270%. The average price for a used Model Y hit a new low in July, down 41% since July 2023, Marketcheck said.