IT was billed as the high-tech durable banknote which would last twice as long as the old fiver.

But now it appears that there could be a serious flaw with the new plastic £5 note as it can be wiped almost totally clean of ink using only a simple pencil eraser.

Print Centre Manager Stuart McLean was experimenting with the note and decided to put it to the test using the type of rubber normally deployed to eradicate pencil marks.

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To his surprise the everyday item was capable of scoring off large parts of the note's blue dye, leaving only security numbers and the see-through hologram behind.

The polymer note, which has been issued by Royal Bank of Scotland, Clydesdale Bank, Bank of Scotland and the Bank of England, is smaller than traditional fivers and said to last 2.5 times longer.

Produced from a thin, transparent and flexible film made of polypropylene, it is designed to not get dirty or crease as much as cotton paper notes, which have been in use for more than 100 years.

The film is coated with an ink layer which enables it to carry the printed design features of a banknote and allows the inclusion of windows or clear portions in the design, used to enhance protection against counterfeits.

Banknote manufacturer De La Rue say it can survive a spin in a washing machine without losing its colour, but Mr McLean said that it could not stand up to an abrasive surface.

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He said: "I had a bit of down time at work and we were talking about the new note, and I happened to have one on me so I got it out and noticed it had a dirty mark.

"I used a pencil eraser to rub it out and I found that the ink underneath rubbed away as well. I kept on going and was able to turn one side completely white.

"I find it very strange that it could be as easy as that to basically erase a bank note and it's something which would not be possible with the old one."

Mr McLean, who works in Cambuslang, performed the experiment on a Clydesdale plastic note, which features an image of the Forth Bridge and has been issued to commemorate the bridge's 125th anniversary and a portrait of Sir William Arrol.

However, he was also able to reproduce the effect on Bank of England note, rubbing out the world 'England' to prove the banknote's vulnerability to a colleague.

He added: "It's not supposed to be as easy as this to get the ink out, and it's like it just simply isn't immersed into the fabric of the note like the ink on a cotton paper note.

"There's something wrong with this, and makes me wonder about the £10 note that coming out soon. I find it hard to believe that all the stress tests the £5 note was subjected to didn't pick up that it is as easy as this to remove the ink."

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The disappearing ink uncovered by Mr McLean is not the first time flaws in the £5 plastic banknote have been picked up. Within days of its launch it was found that it could be shrunk to a fraction of the size if it was exposed to high heat.

A spokesman for De La Rue said that notes would not normally lose their ink, and insisted that Mr McLean's had been subjected to "excessive and abnormal ink wear."

He added: "Whilst ink wear is the ultimate failure mode of polymer banknotes in circulation, the ink wear displayed here appears to us to have been achieved by a method not representative of what happens to a banknote under normal circulation conditions."