Mercedes taking a close look at McLaren upgrade after British GP performance
McLaren finished second and fourth in last Sunday's British Grand Prix with Lando Norris and Oscar Piastri respectively while seven-time world champion Lewis Hamilton was third for Mercedes and George Russell fifth.
Norris's podium was his Mercedes-powered team's first of the season after a poor start.
The race at Silverstone was won by Red Bull's Max Verstappen, the double world champion's sixth straight victory and the team's 11th in a row, but the battle behind is intense with fortunes fluctuating according to upgrades.
"We keep an eye on all the teams as they upgrade," Allison said in a British Grand Prix debrief, explaining that photographs were taken to monitor changes.
He said Mercedes would be paying more attention than normal to McLaren's package.
"We note when something new or unusual comes along. The interesting and unusual thing about the McLaren upgrade is that its lap time effect is quite strong. It's unusual to have a step of that size of relative competitiveness in the middle of a season and chapeau to them.
"They've done a good piece of work there, but that also makes it interesting for us because we have the before and after shots and we know the lap time effect was big.
"We know that whatever changed has made a meaningful difference to their lap time. It's quite useful for us to know what that was and see whether it can play into our own thoughts of developing our own car."
Allison said there was more development to come at Mercedes, even though teams will increasingly be turning their attention to 2024, and improvements to carry into next year.
"For us yes, you will see the upgrades coming for a little while longer. I suspect for the others too," he added.
"What you will get in this next sequence of races is a little bit of yo-yo-ing for position in a very closely packed bunch as upgrades make the difference for one team for a while, until someone else will come out of sequence with another upgrade a race or two later to even things back out.
"Where it will all settle down for the final quarter to one-third of a season, we will see."