Tesla's 'affordable' Model 3 has been subject to fluctuating prices ever since the cost of the electric car in Britain was revealed five months ago, This is Money has found.

When the price was officially announced on 1 May, the US manufacturer said the cheapest version - Standard Range Plus - would cost £38,900, inclusive of the Government's £3,500 plug-in grant.

That price then shrunk as low as £36,490 by the beginning of August before being wound back up to £38,500 as part of a 6 per cent hike across the Model 3 range by September.

This sporadic pricing structure means potential buyers need to time the purchase of a Model 3 - and other Teslas - wisely.

Price hike: Tesla has increased the cost of its Model 3 saloon by 6% across all three variants, This is Money has found

The latest increase, which has seen the prices rise by between £2,010 and £2,860, was introduced just days after the SMMT confirmed it was the third best-selling car in August

This is Money was alerted to the shifting pricing after spotting a sneaky hike on its in-demand Model 3 electric car at the end of August, with the costs jumping by between £2,000 and £3,000 depending on vehicle specification.

Not only did the Standard Range Plus go up by £2,010, both the more expensive Long Range and Performance variants had increased 6 per cent.

The Long Range now costs £47,000 - up £2,510 from £44,490 weeks ago - and the highest-spec Performance has risen from £49,140 to £52,000, which is an extra £2,860.

That was a blow for potential buyers, as it came only months after a cut - with the Standard car's price tag reduced from £38,900 at launch to £36,490.

The most recent rise came just weeks after it was confirmed that the Model 3 had become the third most-registered model throughout August - the first time any electric vehicle has appeared in the top 10 best sellers for a single month in the UK.

A Tesla spokesperson confirmed to This is Money that the price 'adjustment' had been introduced around a month ago.

However, they refused to directly link price changes to the movement of the dollar against the pound, denting any potential buyers' hopes of another cut after the pound rose strongly against the dollar on optimism about a Brexit deal last week.

A screen grab taken from Tesla UK's website on 17 August shows the price of the Model 3 before the hike

Model 3 customers have had to wait for up to 3 years for the Model 3 to arrive on UK soil, with first deliveries landing in June

When asked why prices are fluctuating so frequently, the spokesperson said: 'Like other car companies, we periodically adjust our pricing.'

However, industry insiders who track the price of new cars told This is Money that other manufacturers don't make such frequent and substantial changes to prices, providing a more consistent pricing platform.

There has been plenty of evidence of the US electric car-maker - headed by entrepreneur Elon Musk - altering the price of its full vehicle range in recent years and for a variety of reasons.

For instance, in March it said it was increasing the price of the Model S saloon and Model X SUV by an average of three per cent in a bid to keep some of its stores open.

Price hike comes as Model 3 first UK deliveries arrive

The Model 3 was expected to be Tesla's answer to an affordable battery-powered family car.

It had originally suggested for almost two years that the entry-level Model 3 would cost from between £30,000 and £35,000 before the UK figure was eventually released in May as being £38,900 - the priciest it has been yet.

The hike has come just weeks after the Society of Motor Manufacturers and Traders unofficially confirmed that the Model 3 was the third most registered vehicle in the UK last month.

It was listed in the rankings of the top 10 best-selling new models of August as 'other' because Tesla withholds details of which models it has sold in the UK and doesn't split its sales figures by country.

The Model 3 was unofficially confirmed as the third best-selling new car of August, though the SMMT lists Tesla variants as other because the brand doesn't share full details with the body

The Model 3 is the first battery electric car to appear in the top 10 most registered cars of a single month since records began

This is unheard of for an electric vehicle and the first time a car emitting no exhaust emissions has been in the top 10 most registered models for a single month.

While it's an outstanding achievement for any pure electric car, it hasn't come as a huge surprise given that the first batch of UK models have been arriving since the end of June.

There is still a huge backlog of orders for the zero-emission vehicle in the UK and around the world, which date back more than two years for the most eager customers.

Motorists are expected to pay the full price of the vehicle at the time they placed the order, so won't be subject to this recent hike.

Some 2,082 Model 3s were registered in August, though that's almost half as many as the UK's long-standing favourite car, the Ford Fiesta, which was again the most popular model in August with almost 4,000 registrations.