Armitage, the brother of Test full-back Delon, has been promoted from the second-string Saxons following the broken ankle suffered by Lewis Moody.

Johnson said: "Steffon has been in very good form for London Irish this season and deserves his opportunity."

There has been an increasingly vocal lobby for the 23-year-old's first Test inclusion this season after a string of fine performances for the Exiles.

However, he appeared a long shot to feature in the RBS 6 Nations, which begin in less than a fortnight, until Leicester flanker Moody broke his ankle on Thursday - an injury that could rule the 30-year-old out for up to three months.

As well as Armitage, Johnson has also summoned Bath captain Michael Lipman to the elite squad's warm-weather training camp in Portugal.

He is scheduled to fly out this evening and will then be assessed by England's medics after being knocked out in yesterday's Heineken Cup clash with Toulouse.

Johnson would welcome any reinforcement for his back row after losing Tom Rees for at least the first three matches, in addition to Moody's longer-term absence.

Winger Ugo Monye has not travelled to Portugal in order to undergo treatment on a sore back, while Saxons trio Ben Kay, Matt Banahan and Joe Worsley have joined the squad to provide back-up ahead of the RBS 6 Nations opener against Italy on February 7.