Many homeowners have knockers on their external doors and these items have a significance that should not be underestimated.

This is according to Edwin Heathcote, who pointed out in a Financial Times article that Finnish architect Juhani Pallasmaa calls the items the "handshake of a building".

He stated: "The totem of the front door is the knocker, a mechanism which announces arrival and allows the visitor to engage with the building."

The writer said ironmongery on wooden doors presents one of the few moments when people physically engage with the structure.

Mr Heathcote went on to suggest that one of the oldest and most familiar motifs is that of the hand. Many such objects also bear a ball which is used to knock against a back plate.

Other popular versions found on external doors include a fox or lion's head.

However, the most prolific designs are now abstract compositions, he claimed.

Meanwhile, once people enter a property, it is door handles that enable them to move from room to room, he said.

The expert commented: "Your progress through the house defined by a series of grips and twists which, apart from the handrail on the stairs, are the only moments you get to engage with the materiality of the interior."

Many modern handles on wooden doors use rotating motions, he went on to point out.

He added: "Each user leaves their trace on the timber, older examples polished to a dark sheen through the wear of the traces of oil from thousands of hands."

The most common type of handle is now one that utilises a bent metal tube, Mr Heathcote claimed.

There are many options available to those seeking doors - whether they want handles, knockers or just plain items. One of the easiest ways to search for them is online, where some of the best deals can be found.