Jim Armitage: Amanda Staveley's suing Barclays for £300m over those deals in the desert

Outlook Battle is about to commence between the deal maker Amanda Staveley and Barclays. Yesterday we reported that the queen of deals was preparing to sue the bank over the £7bn Middle Eastern fundraising she helped them with at the height of the financial crisis.

Now, I'm told, not only has she appointed lawyers and a QC, but she is just weeks away from filing a claim – modern parlance for a writ – demanding what I calculate to be the thick end of £300m.

That's how much she reckons her PCP Capital Partners business was shortchanged on the deal after Barclays paid a third party in Qatar a peculiar £320m fee.

It's the last thing Barclays chief executive Antony Jenkins needs. The Financial Conduct Authority has already said it's minded to fine the bank £50m for its "reckless" behaviour over the fee, and the Serious Fraud Office is also investigating.

The story goes back to 2008, when the British government was pressurising Barclays to accept a taxpayer bailout. Chief executive John Varley found the idea utterly abhorrent and set about raising the money Barclays needed privately.

Ms Staveley raised £3.5bn for Barclays in Abu Dhabi, with PCP standing as principal on the deal through two of its investment funds. Barclays' Roger Jenkins led fundraising in Qatar for another £3.5m.

Ms Staveley's claim will argue that, at the outset, it was agreed that all parties would get the same fee in return for their investments. Such a "parity clause" is standard practice in such cases to protect investors from another receiving preferential treatment. The fee paid to PCP and others is not known, but reportedly totalled in the order of £100m.

Understandable, then, that when it emerged in September in the FCA's warning notice that Barclays had made a £320m payment, Ms Staveley started seeking legal advice. If Barclays had paid a Qatari third party £320m, shouldn't she and other investors get paid the same?

Unfortunately for Barclays, it is unable to comment due to the ongoing nature of the investigation. So it's up to me to don the QC's wig on its behalf and propose a theoretical defence. I would guess that Barclays will deny the £320m payment was a fee for the Qatari investment and therefore was not subject to the parity agreement with PCP (Barclays refers to it as an "advisory services agreement" rather than a fee). Alternatively, it could claim that the £320m was split between the two fundraising rounds in 2008, of which Ms Staveley was only involved in the latter. Furthermore, I'd also guess it will claim that it can take no action on the civil claim while the SFO investigation is ongoing.

How long we will have to wait for results from the SFO is unclear, although it has said there will be developments in the early part of this year. One strategy I would not be pursuing, were I Barclays' QC, would be sticking my head in the Arabian sand and hoping Ms Staveley will go away.

I recall another High Court case she brought a few years back against a Ukrainian billionaire. She claimed he owed her a fee for persuading Dubai World to sell him a building on Trafalgar Square.

After his legal team attempted to trash her reputation in court, the Ukranian settled out of court, paying her a hefty seven-figure sum.

Don't be surprised to see Barclays do the same. This is not a woman to mess with.