bright red post boxes have been one of the most recognisable sights on Britain's streets for more than 200 years.

But after more than a century of being manufactured solely in Scotland, there are fears the last of the classic cast iron designs has left a foundry in Stirlingshire.

Machan Engineering, based in Denny, has been the only manufacturer of the various types of post box for Royal Mail since the 1980s. However, concern has been raised because it has received no orders for more than a month for the first time in the company's history.

It comes as new stainless steel models are now rolling off the production lines in Newcastle-Upon-Tyne.

Question marks are hanging over the workforce in Scotland, as well as the nearby firms that provide the raw and specialised casting.

Royal Mail said it would order the cast iron boxes as and when required, but the firm said the expertise and suppliers would no longer be around to make them.

Managers at Machan began to fear the worst when the usual glut of orders at this time of year, stemming from damage done to smaller lamp boxes from youths setting off fireworks in them, did not materialise.

The firm was then made aware of the manufacture of new stainless steel models by the firm it is subcontracted to provide the boxes to, Romec.

Machan director Lisa MacDonald said the combination of new models and the refusal of the contractor to say if and when new orders would be placed has the firm expecting and planning for the worst.

Ms MacDonald said: "We have a small staff of about 10, three of whom make the post boxes, including a father and son team. We are now in the position it is likely they will have to be laid off.

"It is not just us. The pillar boxes are cast at Ballantynes in Bo'ness and the lamp boxes at Specialist Castings, two small family firms.

"We have never had a block of time this long where the orders have dried up. I can't keep staff on in the hope new orders may come soon."

She said all indications pointed to a withdrawal from Scotland, which she believed coincided with the privatisation of Royal Mail and next year's independence referendum.

In the past year Machan has produced 50 of the classic cylindrical post boxes, four of the large oval 'C-Type' boxes used for larger mail and 600 lamp boxes.

The last order was made on October 9, less than a week before Royal Mail was floated on the London Stock Exchange.

Although Machan has now diversified into other types of street furniture, such as bollards and benches, the loss of Royal Mail work will have major implications for the workforce, which has had families making the post boxes for 60 years.

Up until 1980, the manufacture of the cast-iron boxes was carried out by Allied Ironfounders in Falkirk, Lion Foundry in Kirkintilloch and Carron Company in Falkirk, with Machan started by former Carron employees after it went into receivership.

Each box is made by hand and the process has changed very little over the years.

In addition to manufacturing post boxes, Machan's other projects include producing the columns on which hanging baskets are placed in Glasgow City Council parks.

It has made stainless steel seating for Stirling University and bollards that were put up outside the main entrance to Glasgow Airport to prevent terrorist attacks after a Jeep was driven into the main terminal and exploded in 2007.

A Royal Mail spokesman said: "Our arrangements for the manufacturer of cast iron post boxes remain in place. We will continue to place further orders for cast iron post boxes as and when required."

Romec was unavailable for comment.