Last month, a unified police operation resulted in the arrests of 58 people across the UK for offences relating to metal theft. The rise in metal robberies is growing and the police and the government are both making continued attempts to curtail it, which is far from a victimless crime: the Association of Chief Police Officers describe every incidence of metal theft as 'an attack, in some form, on our communities'. Railway disruption caused by lineside cabling – described as 'second only to terrorism' in the British Transport Police's priority list – and moral outrage from robberies of war memorial plaques, statues and church roofs frequently make headlines, but the disappearance of road signs are a major concern too.

Firstly, it is a safety issue: many traffic signs warn of dangers ahead and their loss could result in serious accidents. To a lesser degree, the disruption and inconvenience of a driver getting lost is not insignificant. But to the sign-making industry it also represents a necessity to alter the substrates used to manufacture outdoor signs to ensure they don't get stolen; a sign company that only uses metal substrates may be overlooked by councils in favour of those offering plastic alternatives that won't need replacing due to theft. Indeed, the very fact that metal signs are being stolen is borne of the escalating prices of steel and aluminium, at a time when many sign-makers are still battling with the tail-end of the recession.

Many sign-makers are offering signs made from GRP and other plastics to deter metal thieves

So what are the alternatives? Fibreglass, or glass-reinforced plastic (GRP), is offered by a number of UK sign companies, and is promoted as not only less attractive to thieves but also offering better strength and weight properties compared to metal, making it cheaper. Willenhall-based Morelock Signs is the only supplier of Morelock Permanent GRP (MP GRP), which it claims is the only GRP substrate tested to the BS EN 12899-1:2007 standard to meet approval for inclusion in permanent fixed vertical traffic signs, as well as passing compatibility tests 3M Reflective Sheetings.

Signs made with MP GRP do not appear significantly different to metal road signs (some I've seen feature a label on their backs stating 'MP GRP' – This Substrate has No Scrap Value' to put off potential thieves) but still offer strength and stability: Morelock Signs shows a video of a crash test involving a passively safe post made of MP GRP and Spectralyte where the sign face survives a collision. Morelock Signs also emphasises MP GRP's resistance to graffiti and its relative price stability compared to metal.

The downsides of fibreglass materials are the difficulty in recycling them (a benefit of metal at the heart of its desirability to thieves) and health concerns during its manufacture. In the USA, meanwhile, Image Microsystems has won awards for the eco-credentials of its MicroState signage substrate, produced from post-consumer e-waste plastic – essentially turning used computer cartridges and discarded consumer electronic equipment into hard-wearing signs. Image Microsystems explains that these plastics contain UV inhibitors and brominated flame retardants, making it unsuitable for landfills as it is 'virtually non-biodegradable'. The company also cites research carried out by Texas Tech University's Industrial Engineering Department which found that a MicroState sign has a quarter of the carbon footprint of equivalent aluminium signage. It also proved more durable than aluminium in 'many cases', according to the study, says Image Microsystems.

Image Microsystems isn't the only company to turn waste into substrate, of course: sign components manufactured from recycled plastic bags and other household waste are offered by a host of UK sign companies, although these tend to be aimed at gentler applications such as welcome signs and fingerposts that don't have to contend with the demands pressed on traffic signs.

While research into alternative substrates, especially those fabricated from recycled materials, is surely a benefit to the sign-making industry, it is hoped that the threat of metal theft will be countered by a change to the law. New legislation will require anyone selling metal to recyclers to be paid by cheque or to provide their bank details rather than handing over cash, in order to create a paper trail for every transaction. Those committing offences under the existing Scrap Metal Dealers Act will also face higher fines. "The government is taking urgent action to tackle metal and cable theft head on," Lord Henley, Home Office minister for Crime Prevention and Anti-Social Behaviour Reduction said last month. "Days of action like these are sending a clear message that metal theft will not be tolerated."