McLaren technical director James Key believes all four Formula 1 engine suppliers have now largely converged.

Since the V6 hybrid units were introduced back in 2014, everyone has been catching Mercedes, which of course has played a large part in the dominant success since.

Gradually, however, the gaps have closed and that was particularly the case last year for McLaren's engine supplier.

“I think one of the positives from last year is Renault made a very visible step forward, data and straight-line speed and so on, and that was definitely part of how the team improved last year,” Key told Crash.net.

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“I think the competitiveness – although we saw the Ferrari steal a bit of a march – the competitiveness of the Renault engine was pretty good last year and very much in the mix with Mercedes, and Honda weren’t so far away either,” he said.

“We’ll see how we go now going into this year, but the times when PU were vastly different, which wasn’t that long ago, pretty much disappeared last year.”

This season could actually see the convergence continue as Ferrari, who Key noted jumped ahead last year, could be pegged back by the FIA's technical directives over fuel flow and oil burning.

Mercedes do believe they have made big gains, however, but it's unlikely they will have the kind of advantage seen previously.

Looking further forward, power unit regulations are expected to stay largely untouched until the next big change in 2025/26, with even the suggestion of an engine development freeze put forward to reduce costs.