A Glasgow city centre landmark is about to become even more prominent. The 170,000 sq ft Skypark, a massive glazed office development at the corner of Finnieston Street and the Clydeside Expressway, is to have up to 40,000 sq ft of new space added to the roof.

Owner Allied London & Scottish Properties is planning to put a two-storey ''penthouse'' on to the top of the existing building. The expansion could be used to provide further office space, or for a new city centre hotel.

Douglas Wheatley of Allied London & Scottish Properties says: ''The hotel market in the city is looking rather crowded at the moment, but putting a different use on to the roof would expand our portfolio of activities.

''Alternatively, with our office accommodation now fully let we see an opportunity to take advantage of the buoyant market.''

The rooftop proposal has detailed planning consent and will be designed to provide flexible accommodation, which can be tailored to the needs of occupiers taking a pre-let on the space.

Apart from its location and extensive car parking, the Skypark's other big selling point for occupiers is its price. Wheatley and his team aim to keep occupational costs around 30% cheaper than those charged elsewhere in the city for similar ''secondary'' properties.

Letting agent Ewan Cameron of Ryden says: ''Rentals are around #11 per sq ft, compared with #14 or #15 for secondary locations in the city centre. Business rates here are around #3.50 per sq ft, compared with #6 elsewhere. And our service charges of #1.50 per sq ft are half the charge paid in most other buildings of this type.''

Skypark, which is linked with the neighbouring Clydeway Centre on Finnieston Street to provide a total of 500,000 sq ft of light industrial and office space, has some 600 parking spaces - which are available to tenants at #500 per space per annum.

The Clydeway Centre, which is also owned by Allied London & Scottish, is about to be upgraded via a cladding project which will transform the exterior of the building and enhance the shops at street level.

''With 500,000 sq ft available on one site, split 50/50 between office and industrial, we can shift tenants around to suit their expansion or contraction requirements. This is a very flexible and cost-effective space in which to locate a business,'' says Wheatley.

Meanwhile, a small business park just on the edge of Glasgow city centre has changed hands in a #10.9m deal.

Norwich Property Trust has purchased Berkeley Square, a courtyard development on Berkeley Street just west of Charing Cross comprising 63,000 sq ft of office space in four pavilions. The scheme comes with 111 secure parking spaces in the basement.

The entire development is let to ScottishPower until March 2023, with a tenant's break option in 2014.

The seller was City Business Parks Ltd, represented by property consultant Speirs Gumley.

The purchaser was represented by Mark Fleming of FPDSavills, who says: ''The investment was particularly attractive because it offers flexible open plan accommodation. It has good parking and is close to the city centre.''

Elsewhere in the city centre, the Littlewoods store at 226-238 Sauchiehall Street has been sold as part of a #15m package. Landlords Resolution Property Plc has sold its Glasgow and Cheltenham Littlewoods stores to Henderson Investors for #15m.

Both properties are let to Littlewoods for the next 22 years.

The Glasgow store provides a total of 80,000 sq ft of space, of which 25,400 sq ft is used for ground-floor retail accommodation. The entire store is let at a current rent of #545,000 per annum.

The seller was represented by CB Hillier Parker and Lunson Mitchenall, while Eric Young & Co and Strutt & Parker advised the purchaser.