Denis O’Brien is well known in business and media circles for taking a rather muscular approach to his opponents and critics.

He may need to beef up a bit in the gym when you look at the financial pecs on some of the characters ranging up against his Digicel cash cow.

Digicel created the bulk of O'Brien's €4.3 billion fortune during the noughties by terrorising the then sleepy Cable & Wirelss Communications (CWC) in the Caribbean.

As CWC napped, O’Brien’s more nimble company destroyed its dominance through brilliant marketing and innovative offerings.

All has changed once again following CWC's $3 billion (€2.4 billion) deal this month to buy Columbus Communications, a Caribbean fixed-line provider backed by US billionaire John Malone, who emerges with a 13 per cent stake in the resurgent CWC.

Digicel and CWC have been doing the corporate equivalent of sticking their tongues out at each other in recent weeks over the Columbus deal.

CWC accused Digicel of “sour grapes” because it missed out on the deal, while O’Brien’s company teased its rival for “overpaying by $1 billion”.

Digicel has been roused because it is rattled. The company is pouring a fortune into an extensive fibre rollout, as it looks to cement its future in the fixed-line market.

At a stroke, CWC has leapfrogged it by combining with Columbus. Malone, whose personal fortune exceeds O’Brien’s by about $2 billion, isn’t the sort of chap to cower under the duvet at the thought of a bit of competition.

Neither is Carlos Slim, the Mexican gazillionaire whose $80 billion net worth is ten times that of O'Brien and who is standing in the way of any meaningful further expansion by Digicel in Latin America. The two men have crossed swords in the past and an uneasy truce reins, but that may not last forever.

Digicel has complained bitterly this year about the corrosive effect on its mobile revenues of internet telephony services, picking on Viber in particular.

Viber was bought earlier this year by Hiroshi Mikitani, the Japanese Denis O'Brien. He too is worth $2 billion more than the Irishman and loves a challenge.

At the beginning of this year, O’Brien promised a “massive push” by Digicel and a change in the telecoms “world order”. He has delivered on his promises in the past, so perhaps he is hiding a haymaker for his competitors behind his back. But he needs to produce it soon.

Digicel has missed out on three potentially transformational deals in recent years.

It lost in Burma, it missed out on the $1 billion Orange business in the Dominican Republic and now it has let Columbus escape.

It has about $6 billion in debts, all denominated in US dollars. But a huge chunk of its revenues are in the local currencies of Haiti, Jamaica and Papua New Guinea. The dollar is strengthening against all of them, which means Digicel is running just to stand still on its debts.

Digicel made O’Brien a billionaire, but it is not the cheeky upstart it once was.

It is now in the crosshairs of other, beefier billionaires. It would be uncharacteristic of him, but O’Brien might be better off checking out of Digicel altogether.