I asked a friend who lives near Liverpool and has done a lot of travelling throughout Europe. I asked him if one can survive on 30 euros a day (SGD6000 - SGD1500 for flight to London and the remaining amount divided by 90 days then converted to euros) if one sticks with hostels.
He said that that amount was more than sufficient to cover accommodations but transport, food and attractions will raise the cost. I followed up by asking can you do it all on just the 30?
Waiting to see what his reply is.
I did Europe (Belgium, Holland, France, Monaco, Italy, Austria, Czechoslovakia, Yugoslavia) two decades ago and my budget was less than that. Did it almost all through youth hostels and cooking my own food sometimes.