A US court ruling has approved T-Mobile’s proposed acquisition of Sprint, leaving the third and fourth largest mobile operators in the US free to merge.

The New York Times reported that the ruling judge, Judge Victor Marrero of United States District Court in Manhattan praised T-Mobile at the ruling, saying the company is “a maverick that has spurred the two largest players in its industry to make numerous pro-consumer changes”.

The merger is set to close by 1 April.

AT&T and Verizon may well have quite the fight on its hands. As per the judge’s comments, T-Mobile, while headed by outgoing CEO John Legere, has disrupted the stagnant mobile industry in the States with lower prices and genuinely good incentives for customers. Legere’s injection of character into the industry was a breath of fresh air, and customers agreed with their wallets, propelling T-Mobile past the ailing Sprint in the market.

In a statement published on Tuesday, Legere said in typical gung-ho fashion, “Look out, Dumb and Dumber and Big Cable — we are coming for you … and you haven’t seen anything yet!”, referring to AT&T and Verizon. Current President and COO of T-Mobile Mike Sievert will become CEO when Legere leaves on 1 May.

As previously reported by Bloomberg, Sprint is expected to be able to sell its subsidiary Boost Mobile along with spectrum assets to satellite TV provider Dish as part of the deal to allow Dish to grow into the fourth major carrier. The merger was unlikely to go ahead if this detail had not been reached as competition authorities assessed the impact on consumers of a shrinking telecoms marketplace.