Greater rigour or streamlined efficiency? Confusion about the real purpose of the looming merger of the Office of Fair Trading (OFT) and the Competition Commission (CC) perhaps explains the ambivalent reaction to the proposals announced on 15 March. Because, as competition advisers have argued since the Government floated the idea of unifying the antitrust agencies last October, those aims can easily come into conflict.

Nevertheless, the Government plans to replace the two bodies by April 2014 with the new Competition and Markets Authority (CMA) and claims to be able to deliver on both goals. As such, the Department for Business, Innovation and Skills has rejected most of the radical options on the table, such as mandatory merger approval or a move to a US-style prosecutorial model in which regulators put their case before a judge. The basic approach is to fold the CC into the larger OFT rather than attempt a structural overhaul of competition enforcement while handing moderate, but not inconsiderable, extra powers to the new body. The single body will run the full range of competition policy from merger control to market investigations and cartel enforcement.

Cleary Gottlieb Steen & Hamilton competition lawyer Paul Gilbert, formerly deputy director of competition policy at the OFT, comments: "The message from the Government is that they want to see more enforcement. Businesses can probably expect that the CMA will bring more cases than there have been to date."

Most contentiously, the bar will be lowered for criminal cartel cases, with the requirement to prove dishonesty to be dropped in favour of a focus on whether there was an attempt to conceal the cartel agreement. This remains by far the most controversial – and least expected – element in the shake-up, with critics arguing the OFT has too little experience of criminal prosecution to warrant handing out additional powers. (Most lawyers believe the OFT's one contested cartel prosecution – the 2010 price-fixing case against four British Airways executives – spectacularly failed due to procedural errors and lack of relevant skills, rather than a lack of powers).

Also contentious are plans to widen the scope of market investigations to include public interest criteria at the request of ministers – a step some argue will reduce certainty for business and open the CMA to political interference.

Other additional powers the CMA will assume are relatively minor, including new civil sanctions to fine companies that obstruct investigations pursued under the Competition Act. The CMA is also set to gain powers to take over competition-related actions being handled by sectorial regulators like Ofgem. Such industry regulators will also be under a new duty to consider whether competition powers should be used as remedies to address criticism that such bodies rely too heavily on sector-specific sanctions rather than competition law.

If there is some inevitable wariness among advisers about the CMA's additional teeth, there is considerably more support for uniting the two bodies.

Though some still hold the belief that the robust checks and balances of the current two-stage competition process is a key strength of the UK's well-regarded competition regime, support has been building for years for a single agency. Critics of the two-stage process claim it is unwieldy and slow and, while it delivers on simple cases and complex matters, it struggles to accommodate mid-range matters.

Many argue that the split also leaves the OFT over-stretched while the CC is at times under-deployed. The existence of the separate Competition Appeal Tribunal further underlines the case to unify phase one and two investigations in a single body, as happens in the US and European Commission cases.

The proposed solution attempts to strike a balance in largely maintaining the current model under a single roof. As such, a two-stage process will be maintained with separate teams reviewing the more serious cases. Crucially, the new CMA will retain the independent panel used by the CC, which is seen as the most effective means of ensuring an unbiased review of substantial cases.

"They have tried to mix the best of the OFT and the CC into one," observes Clifford Chance competition law partner Alastair Mordaunt (pictured), the former director of mergers at the OFT. "My concern is whether it gives the best result. It is like putting Britain's best footballers together and expecting them to be the best team."

SJ Berwin City competition partner Philipp Girardet says: "The proposed changes appear to make sense and probably make the new body a more effective investigator."

In general, the creation of the CMA has been received as a pragmatic response that seeks to preserve as much of what works in the current regime – a contrast to the still controversial and arguably unwieldy break-up of the Financial Services Authority.

What the shake-up does not look set to deliver is much cost saving. It was always clear that merging the bodies while preserving a two-stage process would save little from combined budgets of less than £100m – the Government estimates saving will be as little as £1m.

Indeed, given the supposed economic benefits of robust antitrust policy and the avowed desire of the Government for tougher enforcement, there was never a strong case to press the new agency for cost savings.

Overall, it seems the extension of powers, together with the added clout of a single body to lead competition policy, will increase the watchdog's influence – reflecting a now well-established global push towards tougher competition enforcement.

"In the long term it is certainly going to be a powerful body, there is no doubt about it," adds Mordaunt, summing up the view of many peers. "It is going to be a 'super regulator' with a long reach and power, and business leaders will need to look out."

It seems tougher enforcement takes precedence over streamlining after all.

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Shaking up competition enforcement – key points

- Fees for mergers subject to scrutiny to rise from £30,000-£90,000 to a new range of £40,000-£160,000

- Statutory timetable introduced for merger investigations

- 'Dishonesty' test removed in criminal cartel prosecutions

- Expansion of Competition and Markets Authority (CMA) powers to take over competition investigations handled by industry regulators and new rights to suspend integration of mergers under investigation. CMA able to impose civil fines for businesses failing to co-operate with investigations

- Scope of market investigations expanded to include scrutiny of practices prevalent across different markets and to consider public interest issues at the request of relevant ministers

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