UPDATE 2-FTSE 100 ends higher on miner boost, mid-caps lag for the week

* Rio Tinto gains after saying CEO to step down
* Insurer Aviva among best performing blue-chips for the
week
* Mid-cap index marks small weekly gains
* British economy grows for third straight month in July

(Adds details, updates to market close)
By Shashank Nayar and Ambar Warrick
Sept 11 (Reuters) - London's FTSE 100 ended Friday higher on
gains in mining heavyweight Rio Tinto, and marked its best week
in more than three months as a weaker pound benefited the
exporter-heavy index.
The blue-chip FTSE 100 .FTSE closed the day 0.5% higher
and added 4% for the week, breaking a three-week losing streak.
Insurer Aviva AV.L was the best performing blue-chip for the
week after it said it will sell its Singapore business for S$2.7
billion ($1.98 billion). The mid-cap FTSE 250 .FTMC shed 0.1% and lagged its
bluechip peers for the week as a spike in COVID-19 cases spurred
new curbs on social activity, hurting domestically-inclined
consumer stocks. Pub operator J D Wetherspoon JDW.L was the
worst weekly performer on the index.
"The FTSE 100 has international horizons and the resulting
weakness in the pound (from hard Brexit fears) has boosted the
relative value of constituents' overseas earnings," said AJ Bell
investment director Russ Mould.
Rio Tinto was the biggest boost to the index for the day
after giving in to shareholder pressure to replace its chief
executive over the destruction of two significant Aboriginal
rockshelters. Major miners rose on weakness in the pound and higher metal
prices. The pound has come under pressure from increasing bets
on a no-deal British exit from the European Union.
MET/L
Still, British stocks have lagged their peers in the
developed world as middling economic data and an uptrend in
local coronavirus cases pushed them into a tight trading range
since May.
A recent rout in U.S. stock markets had also extended to
local equities, pressuring the FTSE 100 in particular.
British Airways owner IAG ICAG.L was the worst performing
blue-chip stock for the week after it launched a heavily
discounted capital raising and flagged worsening outlook for the
rest of the year and 2021 due to the pandemic.
While data on Friday showed Britain's economy in July grew
for a third consecutive month, the new curbs on activity are
likely to weigh on growth.