Mercedes won't have "new car" for F1's Australian GP like in 2019

The aero package on last year's W10 changed dramatically after the first pre-season test, as new developments - in part in response to a front wing rule change - came through the system at Mercedes' Brackley base.

Allison said that will not be necessary in 2020 as the rules have remained stable, allowing Mercedes to start testing with a close to definitive car.

"We will be more conventional this year," he said.

"We will still have upgrades for Melbourne that will come in the second week of testing, but the entire new car approach of 2019 won't feature.

"Last year, the regulations were changed quite significantly, and they were decided quite late in the year.

"Under those circumstances, doing a launch car and a week two car gave us the chance to build the maximum amount of learning into our Melbourne car.

"With the regulations being more mature this year, and with the opening stab of the 2020 development already being at the same level as the finish of last year's car, repeating last year's approach would not make sense."

• Mercedes' 2020 challenger
• First images of W11 released

Allison said Mercedes has made some significant changes relative to last year's W10, because just developing the older car would not be enough.

"If we had continued merely to add flourishes to the 2019 baseline, we would have found some gains, but in all likelihood diminishing returns would be kicking in by now," he said.

"We wanted to change aspects of the concept of the car - aspects that would be completely impossible to change within a season - to give us a more fertile platform for the new season.

"We tried to make a few well-chosen architectural changes to keep the development slope strong even though the regulations are now a little bit longer in the tooth."

Explaining the changes, he added: "On top of the conventional fare of winter development we made three investments: one at the front, one in the middle and one at the back of the car.

"At the front we have accepted more structural complexity around the uprights and wheel rims in order to provide a higher performance assembly overall.

"In the middle of the car we have followed the pitlane trend by moving our upper side impact tube to the lower position and banking the aerodynamic gain that comes with this layout.

"At the rear of the car we have gone for an adventurous suspension layout in order to free up aerodynamic development opportunity.

"All three investments were improvements in their own right, but their real effect is to mobilise a raft of secondary aerodynamic gains both during the winter and, we hope, across the season to come.

"We have worked - as we would always - on every square millimetre of the car to try and find improvements in this stable set of regulations."