One of the UK's biggest companies has warned that Scottish independence will lead to "years of uncertainty and hiatus" for the business.

Generator and heating supplier Aggreko, which employs around a tenth of its 5,749 worldwide employees in Scotland, said in its annual report that independence is likely to create "additional administration cost and complexity".

The warning from the FTSE 100 firm is not unexpected after its chief executive, Rupert Soames, appeared before Holyrood's Economy Committee last month and warned that international investors are getting "worried". He predicted the annual report season would see a raft of businesses citing independence as a risk.

Since then, Lloyds Banking Group, Barclays, Standard Life, Royal Bank of Scotland, the Macfarlane Group and Breedon Aggregates have all listed independence in their risk management sections.

But Aggreko also said it would find ways to manage the challenges of independence, pointing out that the UK accounts for less than 10% of its business and therefore it has "plenty of options".

The report states: "Without wanting in any way to enter the political debate on this issue, we have a reporting responsibility to set out in our annual report the risks facing the business, and we believe that Scottish independence could present a number of risks.

"At an operational level, it is likely that we would have to deal with significant additional administration cost and complexity in our UK operations, which we currently run as a completely integrated unit, sharing fleet and people without impediment."

Challenges include cross-border disparities in trade, tax and regulation, and macro-economic uncertainties in currency options and European Union membership, it said.

"It seems that the two options for an independent Scotland are either a currency union with the rest of the UK, or a separate Scottish currency - neither of these options are without risk for our business," it said.

"There is a risk that an independent Scotland might not be able to continue in membership of the EU, and that could impact the terms under which we export equipment around the world.

"At the very least, if Scotland votes for independence we will face some years of uncertainty and hiatus. We will, of course, find ways to manage around this challenge if it arises. The major impact will be in the UK, which accounts for less than 10% of our revenues, and as a global business we will have plenty of options."