You know times are hard when landlords start packing in tacky stalls into the public areas of their malls, or RMUs to use the rather ugly technical term.

You can see their point of view. There's no rental growth coming through and vacant stores are proving harder to fill, so one of the only ways to generate extra income is to pack the open areas of the malls with any market trader who'd rather ply their trade in the warm.

The problem is that this pays no regard to the retail tenants of the mall, who suffer as their customers are drawn away by competing businesses. These newcomers pay much less rent and have no fixed costs but are allowed to set up shop right outside the front door of the established tenants who are the bread and butter of the mall.

The other issue with these Retail Merchandising Units is that they are generally naff and add nothing to the centre's offer.

A visit to Centre Court in Wimbledon at the weekend revealed a lower level where you couldn't move for temporary retailers, ranging from the usual Sky TV and BT stalls to one incredibly tacky jewellery business, where a hand-written notice on crumpled cardboard offered empty jewellery boxes for£1.

Centre Court - a decent scheme, well-let with good retailers - looked awful, but even the best centres are doing it too.

On a visit to Birmingham's Bullring a couple of week's ago, I was surprised to see the very upmarket Hotel Chocolat has a decidedly less-upmarket confectionary stall placed right outside it.

Okay, so landlords are having a bad time, and these temporary retailers will help raise an extra few quid. But at a time when retailers are coming under ever more pressure - and landlords are demanding more investment in fit-outs from their tenants - allowing RMUs in en masse demeans both a centre and its owner.