My first stop was 221B Baker Street :-) One of my childhood dreams. They have created a Sherlock Holmes musuem at this address. The ambience is entirely like 100-years back! Just like we saw in the TV series / movies. One of my proud aquisitions from this museum is a Sherlock Holmes visiting business card!
For those of you who are Sherlock Holmes fans, you can find more details of this place on wikipedia link http://en.wikipedia.org/wiki/221B_Baker_Street . This link gives some interesting facts.
My next stop was the Home of Cricket - Lord's cricket ground! The authorities conduct a 105-minute guided tour of the cricket ground. Thanks to the pre-work planning done by my cousin Ninad who took me around the city that day, I could reach just in time for the guided tour which started at 1pm. The guided tour includes a visit to the Members'Pavilion, including tracing the entire route which a player walks from the dressing room to the ground and vice-versa. Also, a view of the original Ashes urn and an explanation of this history behind it. Most memorable part of this guided tour ofcourse was the 15-minute spent in the visitng team's dressing room! This is the room with the small white balcony visible in the second photograph below. You will recall this was the balcony made famous by Saurav Ganguly when he removed his shirt and waved it around in full view of global audience! That room is reserved as visitors dressing room, and on the boards on the walls in that room, the name of every visiting team player who scores a century or takes 5 wickets in a test match is written. The room has some 20-25 sofa seats where all players sit (in a square area). The tour guide mentioned that the 3 seats overlooking the window are the prime seats and, when India is playing, ALL of them are occupied by Sachin Tendulkar! (I had the pleasure to sit on these seats for few seconds). The other players get to see the ongoing game on the television which is inside the room. When I was staning inside this balcony, on the right side, we could see the bigger balcony stand where Kapil Dev and his devils were handed over the World Cup in 1983 - I couldnt believe I was standing right there! One of the strict conditions applicable to this guided tour was that photography was not allowed in the pavilion and dressing room and the museum, and hence I was not able to take any pictures. These fond memories remain in mind only. Photography was allowed during the visit to the stands, and some of them are pasted below.
Further details on Lord's from Wikipedia are at:
http://en.wikipedia.org/wiki/Lord%27s_Cricket_Ground
I then had to leave the Lords tour mid-way (could not join the visit to the new Media box), since I had to also visit other sights of London. Alongwith my cousin Ninad, I could visit many of the prime attractions - Big Ben, Westminster, London Eye (all only from outside due to paucity of time), London Bridge, Millenium walk, etc. I 
could also walk along the River Thames (from Big Ben end to London Bridge end) in the winter chill (that day incidentally was the coolest day this winter in London). By then, the night darkness has set in, and I had to catch the Heathrow Express train to take me back in time for my flight back to Mumbai. Overall, the visit to London was a most memorable one - was able to cover a lot in few hours thanks to my cousin Ninad.