Stephen Foster: The gloves are off as Omnicom and WPP battle for the Lloyds Bank account

A popular summer game, I'm told, is getting up before your competitors to place your towel on the best sun lounger by the hotel pool.

At the recent Cannes Lions ad festival there was a similar game, although you need to get up even earlier. This is to bag the best place on the beach for your company pavilion, or whatever you call it.

"This year it was all Google, Facebook and Microsoft," one media agency delegate told me. "Not a creative agency in sight."

My friend was making the point that the power in adland has switched from the creators – the ad agencies – to the distributors, big online companies and their "frenemies"' (as WPP's Sir Martin Sorrell puts it) the media agencies.

But creative still matters and there's an interesting punch-up brewing in London between the all-conquering creatives of adam&eveDDB (owned by the giant Omnicom Group) and WPP-owned RKCR/Y&R.

This is a contest, due to take place at the end of this month, for the £100m (€140m, $155m) Lloyds Bank account. Some see this as a "make or break" creative pitch for Y&R in London, one of WPP's four big global creative agency networks alongside J Walter Thompson, Grey and Ogilvy & Mather. If Y&R loses it may not be RKCR/Y&R much longer but CHI/Y&R, with Johnny Hornby's CHI agency (49% owned by WPP) parachuted in to the rescue.

The pitch is so important that WPP has assembled a so-called "Green Team" consisting of people from CHI and Grey (and Y&R, presumably) to work on it from an office in London's trendy Shoreditch, host to numerous ad agencies and tech companies. Sorrell is taking a personal interest.

Most successful independent agency in London

The adam&eve team originally hailed from RKCR/Y&R, breaking away in 2010 to build up the most successful independent agency in London before selling to Omnicom's DDB in a deal that could net the founders £60m or thereabouts between them.

Lloyds has flirted with the agency before and recently awarded it the task of celebrating its 250th anniversary with a campaign featuring ye olde black horse. So A&E is, presumably, in the driving seat. A&E also handles Halifax, also part of Lloyds Banking Group, so the Lloyds team knows perfectly well that they're capable of handling a big bank.

But WPP and its combative CEO are clearly pulling out all the stops here and that's causing a little nervousness at A&E's Paddington HQ. What kind of deal will the mighty WPP, the world's biggest marcoms company valued at nearly £20bn, offer to Lloyds? Money talks, after all, particularly in the world of banking. Lloyds is still part owned by the taxpayer. Will Chancellor George Osborne decide the pitch?

That's unlikely, although some people in the Treasury might have a view. Lloyds is being spruced up for an IPO (initial public offering) aimed at the wider public and every little helps (to borrow somebody else's campaign line).

Ultimately, the pitch should be decided on the basis of who produces the best, most relevant creative work. Adam&eveDDB has proved pretty unbeatable in this regard over the past couple of years, winning 20 or so pitches including the likes of Aviva and Waitrose.

Creative will obviously be important here too – most likely the clinching factor. But there are other factors in play as well in what's shaping up to be the biggest fight between Omnicom and WPP for years.

Stephen Foster is editor of More About Advertising, a former editor of Marketing Week and a London Evening Standard advertising columnist. He wrote City Republic for Brand Republic and is a partner in communications consultancy The Editorial Partnership.