Mr Happy,
"your assertion that immigration was the only cause of population increase."

Not true.
I did not assert that.
I said it was the main cause and ONS agrees.
ONS also says that immigrant fertility is higher than existing population. Would you like a link?

The projections are made by government experts on the best and fullest data available. Projections of current trend.
You did not like the projection for continued high immigration.
You slated me for not quoting the nicer projections for a future with lower immigration. Why?