Limiter la saisie à un format particulier

Function verif_format2(texto As String) As Boolean
     Dim reg As Object
     Dim verif As Object
     Set reg = CreateObject("vbscript.regexp")
     reg.Global = False
     reg.Pattern = "^[P]\s[0-9]{6}\s[A-Z]"
     Set verif = reg.Execute(texto)
     verif_format2 = (verif.Count = 1)
End Function 

Private Sub Worksheet_Change(ByVal Target As Range)
If Not Intersect(Target, Columns("A")) Is Nothing And Target.Value <> "" Then
    If Not verif_format2(Target.Value) Then MsgBox "erreur de saisie"
End If
End Sub

And Target.Value <> "" Then
If Not verif_format2(Target.Value) Then MsgBox "erreur de saisie"

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Not Application.Intersect(Target, Range("B:B")) Is Nothing And Target.Value <> "^[P][0-9]{6}[A-Z]" Then
MsgBox "erreur de saisie " 
End If
End Sub

& Target.Address