As Meghan Markle and Prince Harry's car pulled up outside Edinburgh castle on Tuesday, crowds waved Union Jacks and camera phones were poised to capture the first moments of the couple on their first official visit to Scotland.

As they arrived to witness the one o'clock gun being fired and meet founders of charity sandwich shop Social Bite, eyes fell on the former actress' choice of outfit for the latest glimpse at the pieces which would likely sell out due to 'the Meghan effect'.

Her long Black Watch tartan coat by Burberry worn over Veronica Beard trousers with pearl detailing quickly sold out online, but it was the bottle green handbag worn cross body as she met with those in the crowds which arguably drew the most attention.

The handbag with distinctive gold hardware was the American's second outing of a piece by Edinburgh-based brand Strathberry.

A simple choice in accessories has meant big business for the Scottish brand, who had no idea the future member of the royal family would develop such a fondness for its luxury leather bags and striking design.

Ms Markle's fashion choices have been a subject of interest since her engagement to Prince Harry was announced in November.

The pristine white coat by Canadian brand Line the Label which she wore in the gardens of Kensington Palace for her first photo opportunity sold out in minutes.

Similar to her future sister in law the Duchess of Cambridge, whose own fashion choices led to the 'Kate effect' following her engagement to Prince William in 2010, Ms Markle's outfits and accessories have been selling out minutes after being photographed in them.

For husband and wife team Guy and Leeanne Hundleby, 'the Meghan effect' has caterpaulted their luxury handbag business Strathberry into the limelight.

The couple, who have a passion for beautiful handcrafted leather goods, had travelled extensively around Spain with their children and were inspired by the "generations of craftsmanship and skill in working with leather" in the country.

In 2013, the couple established Strathberry on their return to the UK with the brand based in Edinburgh and their handbags crafted in Spain.

Strathberry bags have a lyrical element to them, Leeanne explains, the shape and signature hardware designed so that the brand's bags would be instantly recognisable.

"The Strathberry collection is defined by its signature metal bar, which is part of our DNA and is inherited from the leather sheet music folios of musicians and performers," Leeanne says.

"Both functional and elegant, the bar is clearly and easily recognizable which was something very important to us from the beginning.

"We wanted people to be able to easily identify a Strathberry bag by looking at it."

Those recognisable aspects of their handcrafted leather bags would be worn on the arm of one of the world's most famous women some four years later.

In December, weeks after announcing their engagement, Ms Markle and Prince Harry undertook their first royal engagement together in Nottingham.

Yet what was surprising for many royal commentators was that Ms Markle carried a tote bag as she met with crowds and talked with representatives from the Terrence Higgins Trust and staff from a local school.

Leeanne and her husband had no idea their burgundy, vanilla and navy tri-colour midi tote would fall under the spell of 'the Meghan effect'.

The pair only realised she had worn it when the calls rolled in asking if the future royal was indeed carrying a Strathberry bag.

"Within 11 minutes of photos surfacing featuring Markle's look, the handbag sold out online and across all international retailers," Leeanne says.

"Similarly, visitor numbers on strathberry.com were up that day by around 5000%."

Apart from the Queen, who is often seen carrying her signature Launer handbag, a brand which holds a royal warrant, many women in the royal family do not carry handbags on public engagements.

Instead many choose to carry clutch bags, which is thought to discourage unwanted handshakes.

Yet Ms Markle has defied this so-called 'royal protocol' with her choice of accessory, her trip to the Scottish capital saw her welcome the crowds with handshakes, her bottle green Strathberry East/West Mini worn cross body as she greeted those who waited patiently for a glimpse to see her.

Fans of the small handbag will have to wait until March before it is restocked, with the Huffington Post remarking that more than 1000 people have their name on the waitlist for the accessory.

'The Meghan effect' has shown a unique fondness for Scottish design. Her Percy sunglasses worn at the Invictus Games, her first public appearance with Prince Harry, were made by Finlay and Co.

The brand, co-owned by David Lochhead from Aberdeen, reportedly made £20,000 after Markle was spotted wearing the tortoiseshell frames monogrammed with her initials.

For Strathberry, 2018 could see a hike in sales thanks to the future royal's seal of approval, with the brand already seeing a higher increase in sales since Meghan was spotted with the bag.

"We estimate that this year sales will increase by 10% to 20% due to increased awareness of the brand caused by Ms Markle carrying her Strathberry bags," Leeanne says.

Agreeing that there is definitely a 'Meghan effect', adding that Ms Markle is one of the "most watched fashion influencers in the world", Leeanne believes that championing Scottish and British designers can only be a positive thing.

"I think it is wonderful for Scotland and fantastic she can give brands , such as ours, the exposure and increased brand awareness globally - whether they or Scottish or non - Scottish."