Formula One's radio ban has come more scrutiny after Nico Rosberg received a penalty for breaking radio rules at the British Grand Prix.

Rosberg received instructions relating to a gearbox issue, and was later hit with a 10 second time penalty after the FIA deemed the instructions to be against the rules.

Red Bull team principal Christian Horner, whose driver Max Verstappen moved up to second place as a result of Rosberg's penalty, insisted that Mercedes knew "all too well" that they were breaking the rules, but admitted that the rule needed working on.

"We need to address this issue at the next strategy group meeting and modify the rule," he said. "I understand what the FIA wanted to achieve with driver coaching, but in the case of technical problems, we must be able to support the drivers."

Mercedes motorsport boss Toto Wolff added: "These rules maybe need a rethink. It needs to be discussed."

Despite the penalty, Mercedes, who plan to appeal the decision, believe they did nothing wrong.

"It was a very critical problem," said Rosberg. "I was about to stop on track, so they told me 'change default' to try and fix it."

"I am sure that we interpreted the rules correctly," added team chairman Niki Lauda

A question of consistency?

The debate of whether Mercedes' radio messages were legal comes one week after Force India were not allowed to inform Sergio Perez of a critical brake problem, but Williams were allowed to warn Felipe Massa of a similar problem.

Force India team manager Andy Stevenson agrees, saying it was no different to Austria a week ago when Sergio Perez could not be told his brakes were failing.

"No one understands why they were (allowed to tell the driver) and we weren't," he said.

"How absurd is that?" Williams' Pat Symonds told Auto Motor und Sport. "How many tens of thousands of pounds did that accident cost the team?"